Jake

Jake (Full name Jake the Dog) is a magical dog, companion and best friend of Finn, and secondary main character in Adventure Time. Finn refers to him as his friend and will often get offended if others say that Jake is his dog. He has Stretchy Powers that allows him to stretch and manipulate his body, which repeatedly comes in handy during their adventures. He is the son of Joshua and Margaret. Jake is 28 years old in magical dog years, but sometimes he acts less mature. He also likes to play the viola alot.

Appearance
Jake is a golden-colored bull dog with large, characteristic eyes. His appearance can change drastically due to his ability to morph. He also wears invisible pants spun from spider webs- made from pixies.

Conductor
The Conductor is the main antagonist in the episode "Mystery Train." Throughout the episode, he comes and goes during the train ride, and begins creeping Finn out. Not until all other suspects are dead is he actually suspected of murdering all the candy people, because according to Finn, it's never the creepy guy who's the murderer. After supposedly "murdering" everybody, including Jake, Finn chases him across the length of the train and after a short mano a mano, he is revealed to be Jake in disguise.

Abilities
Jake has Stretchy Powers, the ability to shape-shift, meaning he can control the size, shape, and dimensions of his body. Not only can he stretch and contort himself and form recognizable shapes from parts of his body, but he can also rearrange his internal organs. One common use of his powers is Key Hand, which he uses to open locks and doors. As shown in "Mystery Train," he is also able to stretch himself to make entirely new people, as long as they remain connected to him. Pen Ward said in an interview that Jake uses his powers lazily and doesn't know their full extent.

In the episode "The Limit," Jake's Stretchy Powers are put to the test. It is revealed that while Jake can stretch his body to incredible lengths, but he does have a limit. As he approaches this limit, his body begins to thin as his body mass is distributed along his increasingly lengthening body, and its becomes hard for him to support himself (at one point he uses his legs and walks along the ground to support his body). If he stretches past his limit, his body completely thins out and he runs the risk of dying.

Jake also has a supernatural sense of smell, as he can apparently smell the specific location of objects from miles and miles away. He also owns a sword and an axe but generally doesn't use them for combat. In "Mystery Train," when disguised as the Conductor he briefly uses a sword to fight Finn, but is easily beaten. Perhaps showing that he is not very skilled with a sword or simply that Finn's own ability with a blade surpasses his. He also has a powerful imagination, as seen in "Rainy Day Daydream." Anything he imagines appears, but only Jake can see it.

He's also shown to be a skilled musician, especially the viola, which can have peculiar powers if certain artists are played, such as summoning snakes when he plays a piece by Mozart. He plays acoustic guitar, as seen when he plays the titular song in "Susan Strong". In "Death in Bloom", Finn describes him as "The musical one..."

He can sense when Finn is about to cry, he says "it's like a mother-daughter thing." Jake can also calm Finn down with his saliva.

Personality and Character Traits
Jake is generally laid-back and tands not to worry about things. He relies heavily on his powers (or Finn) to get him out of any predicament he gets himself into, which is often. He often cracks jokes at serious times, but if Finn is feeling disheartened Jake always has a lecture or a song to cheer him up. Acting as Finn's world-wise mentor, he is always willing to give input and advice about a situation, but his suggestions are usually inconsistent; they range from encouraging a helpful, fresh perspective to ridiculous nonsense. He can be somewhat irresponsible at times, frequently leaving Finn to fight most of a battle on his own, but he always pulls through when he is needed most.

Jake may also be dyslexic due to the fact that he writes backwards, as shown on his note to Finn in "Storytelling."

Jake also is somewhat musical. The biggest factor is how he plays the viola a lot. He has sung a couple times, the most notable time being shortly after the House Hunting Song, when he sings to Finn a song about home being "where your heart is." In the episode "Death in Bloom," Finn even says that Jake is the "musical one" out of the two of them.

At times, Jake can be a bit dark when compared to Finn. Throughout the series, Jake makes some questionable comments and actions that may come off as evil or selfish, whether is this a fact or just for jokes in unknown:
 * In "City of Thieves (episode)," Jake makes several attempts to steal a pair of boots and succeeds to eventually, even after being warned not to do so by Finn. However, he was under the influence of the city at the time.
 * In "The Eyes," Jake seriously asks Finn to just kill the horse that was staring at them, much to Finn's disbelief.
 * In "Freak City" when he and Finn arrive at the burning city of the Rump People, he states that he'll go in town to save only the baby Rump People, imply that he would ignore anyone else in need of his help.
 * In "The Duke," Jake suggests Finn not tell Princesses Bubblegum that he made her bald and green, but instead blame it on the Duke of Nuts. He also tells Finn that some of the deeds the Duke has were bad when that is not entirely true, but it's very possible he didn't know for sure and was only going by PB's word.
 * In the episode Susan Strong he says "We can rule them like gods,angry gods!".
 * In Donny, Jake shows a more violent side when he threatened to gore Donny with horns he sprouted.

Lady Rainicorn
Lady is Jake's girlfriend. In her official bio, it is said she is Jake's girlfriend and that they get along so well because of their common interest in the viola.

It is shown that Jake can understand and speak Korean when he speaks to Lady. A loyal boyfriend, Jake often stops adventuring to make time for her, meeting her everyday at 4:00 on the dot.

In the episode "Go With Me?" they can be seen kissing at Couples Only Movie Night, and also in "My Two Favorite People."

In "My Two Favorite People", Lady recalls a time when she and Jake ran naked through a farmers field, causing them both to blush. This may indicate some level of intimacy in their relationship.

Finn
Finn and Jake are best friends and brothers. They will go out of their way to protect each other. Jake watches over Finn using his stretchy powers to protect him, whether it is shielding him from rain or cold weather, or catching him in mid-fall. Jake is fully aware of Finn's crush on Princess Bubblegum (though Finn still denies it) and even helps him try to win her over. Having been raised together by Jake's parents, the two share a brotherly companionship. Jake often acts as a force of guidance in Finn's life, giving out whatever advice he sees best. Though they have seemingly contrasting personalities, Finn's manic hyperactivity and Jake's genuinely lazy demeanor, the pair make an excellent team and are immensely important figures in each other's lives. It is known that Jake is not Finn's dog.

Tree Trunks
Jake and Tree Trunks share a close relationship, which is similar to a grandmother-grandson relationship. This is shown most of the time, though there was a situation in the episode "Tree Trunks" when she kissed him several times so that he would let her help Finn. Jake appeared later with lipstick marks all over his face, and he was smiling. Later, Tree Trunks tells Finn that she'll accept his apology (Finn had earlier yelled at her) if he would let her kiss his cheek. Finn was about to decline the offer when Jake says "Whoa, let her kiss your cheek, man! It's a once-in-a-lifetime opportunity!" Other than this, there are no references of an unlikely romantic relationship between Jake and Tree Trunks, although they remain close friends.

Marceline
Jake has a fear of vampires, which makes him terrified of Marceline. Marceline cannot help it and likes to scare Jake, but in "Henchman," Jake will not accept the fact that Marceline is not evil, and almost murders her by exposing her to sunlight. However, by Season Two, Jake seems to have accepted that she is not evil and has gotten over his fear of her, as evidenced by the fact that Jake was in Finn's pocket during the events of "It Came from the Nightosphere," and because Marceline attends Finn and Jake's party in "Power Animal" and movie night in "Video Makers." In "Go With Me," Jake doesn't seem to fear Marceline anymore, as he said his fear was based on "ignorance."As shown in the sneak peek of Heat Signature Jake is not scared of Marceline instead they are good friends.

Princess Bubblegum
Jake is very aware of Finn's crush on Princess Bubblegum, so Princess Bubblegum and Jake have a rather strange relationship. They are good friends, though. Jake and Princess Bubblegum rarely speak to each other,but as shown in Mortal Recoil Princess Bubblegum likes it when Jake sings songs.

Others
While Finn and Rainicorn are apparently Jake's two favorite people, he has a number of other acquaintances, listed in his cell phone (see Jake's Phone).

Shelby, an earthworm and friend of Jake, lives in his viola.

In "Memories of Boom Boom Mountain", Joshua, a dog who resembles Jake (but wearing a grey fedora) and Margaret, another dog who resembles Jake (but wearing earrings and a peach hat) find the infant Finn. They were in fact, confirmed to be Jake's parents in the Adventure Time Frederator Blog. (See Joshua And Margaret).

Jake and the Squirrel are enemies, because Jake wouldn't publish the Squirrel's letter in his newspaper advice column, and now the Squirrel wants revenge.

Jake's Subconscious
Jake's Subconscious is a version of Jake in the episode "The Witch's Garden." He is translucent, and appears to be somewhat of a conscience. When he is first seen, he tells Jake that he is right to think that crossing the River of Junk is hard work, telling him instead, to wear a girly hat. He appears later in the episode dancing with the real Jake with flowers in his underwear in order to get the Witch to accept his apology. He dies because he is the former version of Jake with his magic powers (Jake had his powers taken away by the witch earlier in the episode). He is brought back to life after Jake apologizes to the Witch and gets his powers back. The only two people that can see him are the Witch and Jake, as Finn told Jake to stop talking to himself. Though, Finn could have seen him, and told Jake to literally stop talking to himself.

Quotes
See Jake/Quotes.

See Jake's Subconscious/Quotes

Trivia

 * Finn and Jake can accurately tell what time it is by looking at how the sun and how it affects the trees.
 * Confirmed on Pendleton Ward's Formspring, Finn and Jake's parents (presumably Joshua and Margaret) are dead.
 * In "The Witch's Garden", Jake tried to remember how he got his powers, and came up with the idea that he got his powers by rolling in a mud puddle.
 * When Pendleton Ward was asked on his Formspring if the mud puddle that Jake rolled in as a pup was really where he got his powers, Pen stated that it wasn't, and that Jake just couldn't remember.
 * Jake writes a newspaper column titled "Begs the Question."
 * Jake wears invisible pants spun from spider webs by pixies, as seen in the episode "Donny."
 * He does a parody of "Double Rainbow" in a commercial.
 * Jake was confirmed to be a bulldog on Pen's Formspring.
 * Jake seems to have Sanguivoriphobia (fear of vampires), but he may have gotten over that fear because he and Marceline are cool.
 * Jake has a tendency to steal items without realizing what he is doing, as seen in "The Witch's Garden" and "City of Thieves."
 * Jake can be stretched by force as seen in "Ocean of Fear," where Finn stretched Jake's ears to avoid making contact with the ocean.
 * During his flashback as a child in the episode "Crystals Have Power," Jake was shown to have a brother named Jermaine.
 * Jake seems to have a love for babies as seen in "Freak City," when he said he would only save the babies in a burning town.
 * During a station break on Cartoon Network, Finn and Jake were voted the best duo of 2010, surpassing Regular Show's Mordecai and Rigby.
 * It is shown that he can play the acoustic guitar in "Susan Strong."
 * In the episode, "The Eyes," Jake attempts to lure the horse away by playing his viola. He made references to the artists whose songs were played but pronounced differently. The two pieces were "Moonlight Sonata" by Beethoven, and "Eine Kleine Nachtmusic" by Mozart.
 * Pen has stated on his Formspring that Jake might have a sister named Jessica.
 * Strangely, despite being a dog, Jake is seen eating chocolate ice cream in "The Pods" though he previously had stated chocolate would kill him in "Slumber Party Panic."
 * In the episode "The Silent King" Finn says that Jake's insides smell like vanilla ice cream, where Jake claims that it is because a wizard cursed him.
 * Jake was spoofed on an episode of MAD.
 * Jake can understand Korean as seen in various episodes where he translates Lady Rainicorn's words for Finn.
 * Jake really likes ice cream, as shown in "The Pods."
 * Jake has a gender-and-species-swapped version of himself: Cake.
 * In "The Limit," it is shown that when Jake hits the limit of his powers, he turns super thin as his total body mass is dispersed throughout the length of his body.
 * Jake's Conductor disguise resembles Pops from Regular Show.
 * Jake is the very first character to mention the Mushroom War.
 * It is possible that Jake was born in the year 1983 because he is 28 or so ( Adventure Time goes by these years).
 * Even without any memory of himself he is still musical. He may possibly be born with a talent of music.
 * In the episode "City of Theives" Jake tries to cheer up Penny by making a frown and squishing it upside down which scared her; at this he turns around and keeps making snail faces