"Obsidian" is the second episode of Adventure Time: Distant Lands.
In a quick flashback, Elise and a young Marceline are walking alone in the desert, heading somewhere. The flashback quickly shifts to hundreds of years later, becoming the place where the Glass Kingdom, inhabited by the Glass People, now stands.
Back then, the desert was nothing but a wasteland, until it was struck by bolt of magic lightning, thus creating the Glass Kingdom. And for centuries, the glass people have lived there peacefully. They even discovered the "Furnace", which is a cave at the top of a mountain where the glass people can go to to get their cracks fixed. But then, a powerful fire-breathing dragon emerged from deep within the ancient furnace, and it caused destruction in the kingdom by melting everything in sight. Princess Bubblegum was called in to figure out a way to defeat the dragon, with Marceline, Bubblegum's girlfriend at the time, tagging along with her. But after a heated argument between Marceline and Princess Bubblegum, PB unintentionally lashes out at Marceline, and tells her to go home. Heartbroken, Marceline sings an angry scathing break-up song to Bubblegum, which somehow worked on the dragon, and managed to drive the dragon back into the Furnace. Once finished, Marceline shares one final scolding look on Princess Bubblegum before turning her back. In return, PB then says that “they’re done” with an angry look and turns her back as well. However, as soon as the reality of their breakup sinks in, Bubblegum runs away crying. Marceline earned praise and respect from the Glass People, but also lost PB as her girlfriend.
Ever since that event, the Glass People have worshiped Marceline as a Saint, nobody uses the Furnace anymore other than to contain the dragon, and they made singing Marceline's "holy song" (which is just her break-up song, but they got the lyrics wrong) an annual ceremony to keep the dragon from coming back. But as for Marceline and Princess Bubblegum, they never saw or spoke to each other again for centuries.
Now taking place in the future, the current generation of glass people are gathering outside of the Furnace for their annual ceremony. See-Thru Princess, the current princess of the Glass Kingdom, is there on an outdoor stage waiting for them all to arrive. Her royal advisors, Sandy, Limeston, and Sir Soda, hurriedly command her to start the "retelling". Just then, Glassboy, a young glass person with a crack on his head and a big fan of Marceline, arrives and tries to explain why he was late, but the Glass People already know that it was because he was reading; which is why, besides having a crack, he is always ridiculed by his own people; except for See-Thru Princess, who was his only friend.
Through a puppet show, See-Thru Princess retells the story of how the Glass Kingdom was born, and how Marceline saved it from the dragon, whom they named "Molto Larvo". The Glass People, however, made a few errors in their story like mistaking her axe bass for a "silver shovel", and they still have not yet gotten the lyrics of Marceline's "holy song" right. But just as the Glass People are about to start singing her song, Glassboy thinks otherwise. Believing that Marceline has slew Larvo because nobody has seen Larvo since that day, and after reading about how the Furnace can fix cracks in an ancient book, Glassboy tries to convince everyone that the Furnace is safe to use again, and that this was his chance to fix the crack on his head. But the Glass People and the royal advisors disagree with him; and they even made fun of See-Thru Princess for liking Glassboy the way he is. Determined to get his cracked fixed, Glassboy comes up with a plan.
At the dead of night, Glassboy returns to the Furnace, but not before stealing the key that unlocks the second set of doors behind main doors of the Furnace. Upon entering the Furnace, Glassboy finds a pit of lava, and uses a pulley system located near the edge of the pit to lower himself just above the lava flow. Unbeknownst to Glassboy, Larvo is right behind him, and he accidentally wakes him up. Realizing that Larvo is still alive, Glassboy quickly pulls himself back up, and starts running towards the door, with Larvo quickly gaining on him. But while running, Glassboy realizes that he has dropped the key; which, unfortunately, allows Larvo to break through the second set of doors, leaving only the main doors to stop him. Glassboy manages to get out, and lock the main entrance just before Larvo gets out. He then utters the chorus of the "holy song", but it didn't stop Larvo from trying to break out, which triggers the alarm system of the Glass Kingdom. Glassboy immediately tries to leave to avoid detection, but he is quickly caught by Sandy, Limeston, Sir Soda, and See-Thru Princess; and tells them that he was just trying to fix his crack. But the three royal advisors refuse to forgive him, despite that See-Thru Princess believes that Glassboy did not mean any harm; and claim that no song can stop Larvo now. Glassboy pleads that he can fix what he has done by finding Marceline, but Sandy denies this because she assumes that Marceline has been dead for a long time, and then Sir Soda grabs him and drags him to the jail tower. But Glassboy is still confident that Marceline is still alive, prompting that she is probably slaying another dragon. The scene then cuts to Marceline and Bonnie building a small closet together.
A short montage then shows the everyday life of Bubblegum and Marceline living together in Marceline’s house, indicating that PB is finally distancing herself from the constant responsibilities of the Candy Kingdom. The two enjoy each other’s company as they bake, read, sleep and play board games together. Marceline has also been working on a new song, which Bonnie was eager to hear; but Marceline quickly withdraws, and tells her that it's not ready yet. Bonnie, however, happily says that she is willing to wait; and she even gives Marceline a kiss on the cheek. Meanwhile, Glassboy is sitting alone in his cell, until See-Thru Princess opens his cell and leaves his Marceline doll as a clue for him to seek the Vampire Queen out himself. He quickly does and travels across desert and wastelands in an effort to find her. Back at the Furnace, Sandy, Limeston, and Sir Soda are belittling the Princess for releasing Glassboy, making See-Thru Princess blush with insecurity and tries to convince them that she holds faith in Glassboy that he will find Marceline . But they are not convinced, and instead, the three advisors suggest that she should step down as princess. Unbeknownst to them, Larvo is eavesdropping on their conversation and remembered his previous defeat by Marceline. So as soon as See-Thru Princess and her royal advisors leave the scene, he squeezes his mouth between the doors of the Furnace, and placed three black orbs with his tongue. The orbs then come to life, and morphed into the Glassassins tasked with one goal: destroy Marceline.
After traversing far many days, Glassboy stumbles upon Choose Goose in a forest not far from Candy Kingdom, and asks him where Marceline is; to which he answers, in a rhyme, that Glassboy has to go through the Candy Kingdom first. When Glassboy enters the Kingdom’s city, he overhears a voice stating that the following song was dedicated to Marceline. He immediately enters Dirt Beer Guy's tavern and sees a bunch of Candy People listening to Simon Petrikov about to perform. Glassboy tries to gain the man’s attention, but then Smudge grabs him and throws him out for interrupting, but not before throwing his Marceline doll at Simon's face. Fortunately, Simon decides to see Glassboy, seeing that he's a "big Marcy fan". Simon brings him to Marceline’s house, where she and PB are playing a board game. When Glassboy sees Marceline, he quickly approaches her, and bows to his knees in awe of her. He then explains that Larvo has resurfaced, and that the Glass People need Marceline to once more vanquish the dragon. However, both Marceline and Bubblegum are initially reluctant, because the incident cost them their relationship, and it took centuries for it to heal. Bonnie suggests that there are other heroes who can help, but Glassboy quickly cuts her words and says "please" continuously, until both of them eventually agreed to go. But just as they went off on Marceline’s motorcycle, the Glassassins have found the vampire’s house, yet all they saw was a distraught Simon wearing an Ice King cloak, Gunther Slippers and a fake crown in front of the refrigerator, apparently doing it as a coping mechanism for comfort. The Glassassins threaten Simon as he pleaded that he was “too old to die”. But then, one of them takes the Marceline doll, indicating to Simon that they are after Marceline. He confidently says that she had already left, but the Glassassin that took the doll burned it in its grip, showing that they are determined to track her down.
In another flashback from when Marceline was just a child and living in Elise's RV, Marceline is drawing a map with landmarks, while being directed by her mom, Elise. At first, Marceline wants to draw something that she wants, but her mom explains that everything she's telling her to draw is important, to which Marceline agrees. The flashback ends when Elise says that Marceline is going to be a great artist one day. Back in the present, PB is driving the bike through the desert, when they pass by the minivan that Marceline and her mother used as a shelter centuries ago. Marceline asks why are they going that way, to which PB replies that its the fastest route to the Glass Kingdom, prompting PB to question why is she asking, to which Marceline replies that she used to live around those parts. Surprised by her answer, PB asks Marceline when did she live there, but Marceline doesn't open up; which actually makes PB like her more for being "mysterious", just like her new song. After asking Glassboy if he's okay at the back of the motorcycle, PB then says that "this is all gonna go great", and looks to the sky and sees a bird following them.
The trio eventually reach the Glass Kingdom and arrive at the entrance. Remembering their previous visit and being a massive fan of ceremonial tradition, PB rips off her biking outfit to clothes she wore underneath, calmly rings the ceremonial glass doorbell a single time, and eats sand from the "welcome bowl". A Glass Guard slowly pops up, and states that visitors aren't allowed to enter due to lockdown. Princess Bubblegum tries to explain that they are there to help with the situation, but is told that they may only enter by royal invitation. As she tries to use diplomacy, a fed up Marceline kicks the giant bell in the blink of an eye, with Bubblegum watching in sheer amazement of Marceline’s power. The bell falls onto the outer walls and creates a ramp, which they use to enter the city. After landing, neither cheers nor warm welcome greets them, and Marceline’s direct attitude only escalates the tension. PB tries to politely explain, however, they are quickly surrounded by dozens of "Shards", the Glass Kingdom guards, and are approached by Sandy, Limeston, and Sir Soda. See-Thru Princess stops the Guards though, but as Bubblegum tries to greet a fellow princess, she is completely ignored by See-Thru Princess and rushes to Glassboy, happy that he is alive. But the three royal advisors did not feel the same way, now that he has brought two strangers in their kingdom; and they order the shards to take him back to the jail tower. Glassboy tries to tell everyone that he brought the real Marceline, but nobody still believes him, until the Glassassins show up and engage in a battle with Marceline once they see her. Taking all three at once, PB tries to help by shooting streams of jelly beans, but to no avail as they melt upon contact with the Glassassins. The Glassassins then pin Marceline on the front of a glass building, ready to strike. But when one of them tries to strike a final blow, Marceline quickly uses her bass to stop the attack, and it inadvertently hits the bass' cords, which seems to weaken them. Quickly realizing that sound waves affects them, Bubblegum tells Marceline to "turn up the reverb", and seemingly defeats the Glassassins, by causing them to explode; which made Larvo react with a screech. The Glass People are finally convinced that she is the real Marceline, and cheer for her; except for the three royal advisors. PB is happy for Marceline at first, but eventually feels left out as the Glass People credit Marceline again, and ignore her. But while everybody is cheering, the remains of the Glassassins slither away, indicating that they're still alive.
The Glass People then escort the two ladies to the Furnace, while the shards carry Marceline’s bike with Glassboy on it. One of them sprays Marceline with a "cleansing spray", making Bubblegum feel a little envious because it is considered a high honor in the kingdom. Realizing that PB feels insignificant in the eyes of the Glass People, Marceline tries to comfort her by telling PB that she is important to her, giving PB some relief. Having arrived at the Furnace, See-Thru Princess asks Marceline how long will it take for her to write a new “incantation”, but it makes Marceline question at what she means by "incantation". See-Thru Princess then explains that her original "holy song" does not work anymore, and shows the choir repeatedly singing that song. Hearing them sing, Marceline finally explains to them that the song is not working because they've messed up the lyrics for a long time. But when she's about to show them the correct way to sing her song, Marcy first asks Bonnie if she's okay with hearing it again, and PB answers that she should do what she has to do. Marceline then proceeds to sing her break-up song, "Woke Up". The singing continues through a flashback from when Marceline first sang that song, showing how the song defeated Larvo, and how she and PB broke up. After singing, the song seemingly worked, as Larvo stopped trying to break out. PB is visibly disappointed that Marceline's song worked again, but when Marceline tries to console her, Glassboy quickly deduced that the whole song was about Princess Bubblegum; and the Glass People, including the royal advisors, laughed at the song's lack of subtlety and at PB, making her blush out of embarrassment, which makes Marceline growl at them in annoyance for laughing at her. Suddenly, Larvo slams on the door, and breaks a hole with his hand, and hits some of the Glass People, melting them on contact.
Marceline is shocked that her actual song didn't work this time, which made Bubblegum assume that its been centuries since it was last used on Larvo. This presented the perfect opportunity for Bonnibel to put her plan into action. She calls the Morrow, which was the bird that was following the trio in the desert, to bring her the upgraded version of her force field, and then drops it at the entrance of the Furnace; which quickly puts up a bubble-like force field as soon as it dropped them, stopping Larvo from trying to escape. Seeing that Bubblegum has a back-up plan, Marceline is disappointed that PB was expecting her song to fail; but Bubblegum justifies that they never figured out why her song did work, and that her new and improved barrier will buy her time to find Larvo’s true weakness. Meanwhile, See-Thru Princess is being pressured by her royal advisors' questions about what to do now, because they still won't believe that the "outsider" is the real Marceline and assume that her song only made the situation worse. But when Glassboy also puts pressure on her to believe in Marceline, See-Thru Princess finally snaps and lashes out at Glassboy, and tells him to leave her alone for a while, leaving Glassboy hurt by what she said. Feeling that she should be the one who has to defeat the dragon, Marceline insists that she should write a new angrier song, but her usual rock-anger was not the same as it used to be, making her unable to come up with a new angry song. But believing that her negative emotions are still within her, Marceline decides to go back to the origin of her sorrow. Bubblegum pleads her to not go, but Marceline drives back into the desert, leaving Bubblegum alone to deal with the problem.
In the next flashback, young Marceline and Elise are heading to what Elise calls a "secret clubhouse" by using the map that Marceline made in the previous flashback. Having spotted one of the landmarks, Elise is sure they are close to the "secret clubhouse". To keep Marceline's mind off of her hunger, Elise suggests to play an “I see”-game. Suddenly, Marceline spots a mutated coyote puppy saying “Wazzup”, but Elise hits it with a stick, fearing for Marceline’s safety. The mother coyote is angered by what she saw, and attacks Elise. Marceline tries to help but is thrown away by the mother coyote. Out of anger, Marceline uses her soul-sucking powers to suck the soul of the mother coyote, saving her mom but leaving Elise shocked by what she witnessed. The flashback back ends before returning to the present, where Marceline finds one of the landmarks that leads to the secret hideout.
Meanwhile, at Furnace, Bubblegum was able to extract a substance from Larvo's hand using a giant baster, which she then puts on a glass person shaped like a Petri dish. Using giant speakers, PB plays a cacophonous sound at the substance that suddenly comes to life. It jumps at PB, but she quickly stops it by spraying it with root beer from her elemental powers, which crystallizes it in the process. She then overhears the royal advisors demeaning See-Thru Princess for her poor decision-making, and brings up the option of her stepping down as princess.
The next flashback takes place once again on the day PB and Marceline broke up. Princess Bubblegum is struggling to find a way to keep Larvo contained, while reassuring the Glass People that she's got everything under control. However, she can't focus because Marceline, who just wants some attention from PB, keeps distracting her. They also argue if the Glass People are worth saving, to which PB agrees while Marceline shows disagreement by rudely patting on their heads like drums. When Marceline bugs her again, Bubblegum finally reaches her breaking point and lashes out at Marceline, and then tells her to go home. Hurt, Marceline begins to sing her break up song. The flashback then cuts back to young Marceline and Elise, who are in a gas station. Marceline directly asks her mom, who was trying to fix a broken motorcycle, if she was a monster. But just as Elise tried to reassure her daughter, she coughed up blood and understood that she won't be around for much longer. Wanting to protect Marceline from the truth, Elise diverted her focus to the safe-house, which she fabricated as a “clubhouse” because she knew Marceline had to be on her own from that point. But because she refuses to leave her mother, Marceline is yelled at by Elise (who only did it save her daughter) and leaves to find the "clubhouse". Marceline finally arrives at the "secret clubhouse", but to her surprise, the safe-house was not full of people, but rather filled with long-deceased survivors.
Back in the present, Bubblegum informs See-Thru Princess that she has figured out a way to stop Larvo permanently by using her root beer from her elemental powers. However, Bubblegum also warns See-Thru Princess that her plan comes with its risks, which makes See-Thru Princess hesitant because she already feels anxious about the Glass People waiting for her to make the right decision. But Bubblegum is able to convince See-Thru Princess to take the risk by reminding her that as a princess, she must do everything she can to protect her people. Bubblegum then notes that in order for her plan to work, she needs something that can carry massive amounts of liquid, but she doesn't have the resources. See-Thru Princess insists that the Glass People can help, and she convinces them with a speech, despite her royal advisors' protests. The next flashback then goes back to young Marceline in the hideout, where she has assembled inanimate objects and drew on them to fantasize as friends. She then sang a song about the blinking red light in the bunker to the objects, and shared a harsh discussion about blaming herself for her mother’s fears; which also inspired her to be the person she wants to be.
Back in the present, Marceline successfully finds the bunker and approaches the machine with the blinking red light. She accidentally presses one of the buttons and plays a recorded message left by her mother, which revealed that Elise was expecting Marceline to be inside the secret bunker, why she yelled at her, why Marceline had to be on her own from now on, and that Elise assured her that the world won't change her because Marceline has a good heart. Elise then says "I love you" to Marceline, hoping that she can forgive her for what she has done, and then succumbs to her sickness, ending the message. Marceline is distraught by what she has learned, and cries on her knees. Marceline suddenly sees a silhouette of someone at door, which she hopes that its her mom. But its revealed to be just Glassboy, who stowed away on her bike. He came to amp up Marceline, who only wanted to be left alone. Although Glassboy tries to prove that he can relate to Marceline's situation by taking Marceline’s old cardboard guitar and sing "See Through". Hearing the song and finally understanding how her punk-rock-anger actually sounds like, Marceline can’t help but laugh at her own expense. Glassboy still believes Marceline needs to be angrier, but Marceline admits that what she really need is to be with PB. But when Glassboy and Marceline try to leave, they are suddenly met by the Glassassins, who now have merged together into one giant monster with three heads, and has already destroyed Marcy's motorcycle. Marceline quickly brings out her axe bass, but in a flash, they destroy Marceline’s axe base, which forces her to go completely mental and rage filed.
Back at the Glass Kingdom, PB, See-Thru Princess, and the Glass People are standing by, ready for PB to initiate her plan. She starts by shutting down her force field, and allow Larvo to escape the Furnace. Bigger, stronger and angrier, Larvo heads down towards the kingdom, and approaches the two Princesses. Larvo unknowingly walks into a trap, as the Glass People poured massive amounts of root beer on him, crystalizing him rock-solid. The Glass People, See-Thru Princess, and Bubblegum celebrate their victory; but the moment is short-lived when Larvo manages to break free, and it conveniently gave him crystal armor, leaving PB’s face filled with shock and horror. Meanwhile, Marceline confronts the Glassassins for destroying her bass, but she chooses not to fight them because helping Bonnie is more important to her. She then grabs Glassboy, and flies immediately back to the Glass Kingdom.
In the Glass Kingdom, however, Larvo is on a rampage, and is melting and breaking every glass building in sight. Sandy, Limeston, and Sir Soda see the situation as an opportunity for them to do something, but they simply ran right under Larvo screaming. Marceline and Glassboy arrive at the Glass Kingdom just as Larvo continues to demolish the kingdom further, with Bonnie and See-Thru Princess helping the Glass People evacuate. After Marceline and Glassboy meet up with Bonnie and See-Thru Princess, Bonnie urged Marceline to sing a new song, but Marcy reveals to her that her bass has been destroyed, and that she has accepted that it happened. But when Glassboy suggests that he uses his song "See Through", Larvo suddenly approaches all four of them, and quickly takes out PB and Marcy. He then proceeds to Glassboy and See-Thru Princess, and give chase. Realizing that he is the one that Larvo is after, Glassboy knew what he had to do. He pushes See-Thru Princess out of the away to safety, and lures Larvo back to the Furnace by letting Larvo chase him.
Larvo follows Glassboy back to the Furnace, with Marceline and Bubblegum quickly catching up to them. Unbeknownst to them all, the royal advisors had hidden away behind the force field generators and saw this as a chance to trap Larvo again, despite imprisoning the others with him. They cranked the force field to full effect, causing the cave to collapse, which leaves Marceline, Bubblegum, Glassboy, and Larvo trapped inside the Furnace; with Glassboy being knocked unconscious, and Larvo being buried under a pile of rubble. With the cave destabilized, and with no way out, the two sat down and finally reconciled with each other. Marceline apologized for leaving PB, admitting that her difficulty in being honest about her feelings was due to how her mom avoided talking about bad things. Thinking that it was the end for the two of them, Marceline decides to be honest with PB, and let her know how she truly felt through a song. She picks up her old guitar from Glassboy, and starts singing Monster. While Marceline is singing, Larvo, still trapped under a pile of debris, awakens and listens to her song. He then begins to reminisce his own difficult past, from when he was a young tadpole-like creature. Revealing that Larvo’s anger was the result of losing his own family to an ocean predator, and surviving by himself inside a volcano. He also gained a scar on his head from escaping the predator, and used a white round rock to cover it up, which ultimately caused him to evolve into a dragon. After Marcy finishes singing her song, she and Bonnie lean in closer, and the two share a passionate kiss.
Their romantic moment is short-lived when Larvo suddenly rises from the rubble, and roars frantically in emotional turmoil. Thinking that they're about to kick the bucket, Bonnie finally tells Marceline that she loves her, and Marceline admits that she is happy that she gets to die alongside with Bonnie. But just as they're about to accept their fate, Larvo falls to the ground, and then removes the stone that is hiding his scar. Larvo’s scar unexpectedly starts to glow brightly, which causes his entire body to turn into nothing but a black husk as the light fades. From the black husk, a harmless, majestic winged cat-like creature emerges, surprising Marceline, Bonnie, and a reawakened Glassboy.
Outside of the Furnace, when Sandy, Limeston, and Sir Soda are rejecting the idea to shut down the force field, See-Thru Princess finally stands up to them, and uses Sir Soda's sword to destroy the force field. The explosion clears the cave entrance, and allows the winged cat-like creature to leave the Furnace first. As it flies over the Glass Kingdom, the Glassassins return, only to find that Larvo has now changed into the winged cat-like creature. prompting them to also do the same thing, which turns them into several, happy cat-butterfly creatures. Bubblegum, Marceline and Glassboy emerge from the Furnace unharmed, but are shocked to see that See-Thru Princess has been shattered into two by the explosion. Because of the severity of her crack, the royal advisors agree that See-Thru Princess has to step down as princess. However, she rejects by fixing herself, using the ribbon she wears to reattach herself, and then states that thanks to Glassboy, she now realizes that cracks actually make them stronger, rather than label them as outcasts, as they were taught to believe. All the Glass People then revealed their own cracks, which they no longer feel ashamed of having. The royal advisors refuse to accept the change, until a mishap with their "clothes" causes them to accidentally reveal that they have considerably more cracks on them than the Glass People, showing their hypocrisy, and prompting them to run away in shame. Glassboy is finally accepted, See-Thru Princess apologizes for doubting him, and the Glass People also apologize for bullying him for so long.
Just then, Simon arrives, already too late, to warn Marceline about the impending danger (that has already been resolved), and has brought help that consists of a few Banana Guards, Bronwyn and a grown-up Finn. Confused by the people she sees, See-Thru Princess asks PB if they are her friends, to which PB replies that they are, and that she was proud of them. In the Glass Castle, the Glass People, Marceline, Bonnie, and including Simon, Bronwyn, the Banana Guards, and Finn, celebrate their victory by having a simple dance party, with Glassboy singing Eternity With You. Everybody, apart from the royal advisors, are happily dancing to the song, until Glassboy hits a very high note, and causes Sandy, Limeston, and Sir Soda's heads to break into pieces. They are quickly swept away by the Shards, and Glassboy goes back to singing. Bonnie and Marcy continue to dance together, as Marceline complements Bonnie for her looks, and Bonnie concedes that she is happy that she finally gets to dance with her. Marcy then admits that she has a lot more songs to sing, to which Bonnie replies that she looks forward to hearing them, as she has always loved her songs. The episode ends with Bonnie flashing back to the day she and Marceline first met, which was in one of Marceline's concerts, and is where Marceline gave Bonnie her rock shirt by throwing it at her. Marceline then winks at her, while Bonnie looks at her lovingly.
- Princess Bubblegum
- Glassboy (debut)
- See-Thru Princess (debut)
- Larvo (debut)
- Elise (flashbacks)
- Sandy (debut)
- Limeston (debut)
- Sir Soda (debut)
- Glassassins (debut)
- The Morrow
- Choose Goose
- Simon Petrikov
- Glass People (debut)
- Shards (debut)
- Ancient Glass Princess (debut/flashbacks)
- Candy People
- Pete the Punk
- Hunson Abadeer (mentioned in flashback)
- Jake (pictured in tattoo)
- Lady Rainicorn (slippers)
- Gunter (slippers)
- "It's Funny"
- "Remember You"
- "Woke Up"
- "Brush Song"
- "Red Light"
- "See Through"
- "Eternity With You"
- "Welcome to the Glass Kingdom"
- "Glassboy Meets the Dragon Larvo"
- "Glassboy on the Run"
- "Marceline and Princess Bubblegum Domestic Bliss"
- "I'm Too Old to Die"
- "Marceline and Princess Bubblegum Visit the Glass Kingdom"
- "Marceline Breaks into the Glass Kingdom"
- "Marceline Came to Play Hard"
- "Marceline Appears Victorious"
- "Young Marceline"
- "Princess Bubblegum Discovery During a Glassassin Attack"
- "Flashback Marceline and Princess Bubblegum Argue"
- "Marceline Returns to Her Bunker"
- "Plan to Defeat Larvo"
- "Marceline's Reckoning"
- "It's Me Glassboy!"
- "Larvo Strikes"
- "This Thing Really Hates Me"
- "I Love You, OK!"
- "Simon to the Rescue"
- This song was nominated for the 2021 Daytime Emmy Awards for the categories "Best Spacial Class Animated Program" and "Best Writing Team For A Daytime Animated Program."
- Olivia Olson expressed that she felt Princess Bubblegum and Marceline had to talk about their relationship and see how it would move forward, which will be discussed in the special "Obsidian".
- Adam Muto says the title "Obsidian" is a metaphor, as it is the most powerful fusion, and also has to do in the Glass Kingdom. What they want is to focus on Princess Bubblegum and Marceline's relationship.
- "Glassboy" was originally a temporary name, but it stuck and they never ended up changing it.
- As stated by Adam Muto, "Obsidian" takes place a "few years" into the relationship of Princess Bubblegum and Marceline, implying that it takes place not that long after the events of "Come Along With Me", the Adventure Time series finale. However, the exact amount of time remains ambiguous.
- Some of the characters are seen wearing things that reference their pet/best friend:
- Princess Bubblegum repeatedly uses the word "Egress", as she does in "The Hall of Egress".
- The omnichord from "I Remember You" is seen again when Simon is performing "Remember You".
- In a flashback, Marceline is seen giving Princess Bubblegum her Rock T-shirt from "What Was Missing".
- An aged up version of Finn appeared near the end of this episode. A younger version of Finn showed up in the previous Distant Lands special, "BMO".
- The side of Marceline's fridge bears a photo booth strip depicting images of herself and Princess Bubblegum. These pictures make their first appearance in the episode "Ketchup".
- The scorpion bears a cap which contains the Cool S, also known as a "Stussy S"
- The motorcycle which Elise was seen repairing was a 2000 Honda CB600F.
- Glassboy mentions that he enjoys reading Manga, a popular form of Japanese comic publication.
- The RV featured at the end resembles a modified 1977 RAF 2203 "Latviya" Minibus.
- In the bunker, when Marceline sings "Red Light", the cockroach that stood atop the pork and beans could be a possible reference to the film Wall-E.
- This episode fully reveals how and why Marceline and Princess Bubblegum broke up before the events of the series. It also reveals that Marceline gave Princess Bubblegum her Rock T-shirt at one of her concerts and the reason Princess Bubblegum likes smelling it is because Marceline was sweating in it when she gave it to her.
- As stated by Adam Muto, "Obsidian" takes place a "few years" into the relationship of Princess Bubblegum and Marceline, implying that it takes place not that long after the events of "Come Along With Me", the Adventure Time series finale. While the exact amount of time remains ambiguous, Finn has aged considerably since "Come Along With Me", where he was seventeen. Finn is now slightly taller, his hair has darkened from a golden-yellow blonde to a dirty-dark blonde, and he has facial hair, implying that a considerable number of years have passed. Though Finn does come to help, he appears to now take a more relaxed approach to living.
- However, Simon Petrikov does not appear to have aged since "Come Along With Me". It is possible but unconfirmed if that's related to Betty's ambiguous wish in "Come Along With Me" to keep Simon "safe".
- It is revealed in the flashbacks that Marceline's mother Elise did in fact survive the Mushroom War. Following the apocalypse, she and Marceline continued to live in a trailer in the desert (previously seen in "Everything Stays"). Elise came down with an illness (possibly radiation poisoning) and began to cough up blood, which eventually led to her death.
- Jake's fate is unclear as he is not seen with Finn at the end of the episode, with Bronwyn appearing seemingly in his place. Notably, the flowers in his tattoo of Jake resemble Forget-Me-Nots, leading some fans to speculate Jake has passed away. He is confirmed dead by the time Finn is elderly in "Together Again" though it is unclear whether Jake has already passed away at this point in time.
- "Adventure Time Revived at HBO Max" by Andy Swift, TV Line (October 23 2019)
- San Diego Comic Con (2020-07-24). "HBO Max and Cartoon Network Studios: Adventure Time: Distant Lands | Comic-Con@Home 2020". YouTube. Retrieved on July 24, 2020.