Rainy Day Daydream

Synopsis
When a knife storm forces Finn and Jake to stay inside, they discover the out-of-control power of Jake's imagination.

Plot
Finn and Jake are heading out of their Tree Fort, getting ready for a day filled with adventure, and Finn is slapping Jake's jowls for fun. Finn had written a whole list of things to do on his arm, but as he reads it off to Jake, it starts to rain knives. Jake runs inside for cover and Finn stares at the storm in awe, saying that he has never seen a knife storm before. Jake yanks him in and they sit on the couch wondering what to do.

BMO appears and offers that they play Conversation Parade, a game he just made. When he asks, "What do you think about the stars in the sky?" Finn replies, "They're all right, I guess." BMO replies, "That is an interesting response", Finn and Jake find this game boring, and BMO'S batteries run out of energy, so Jake suggests that they use their imaginations. Finn says that only 'turbo nerds' use their imaginations, but Jake starts imagining stuff anyway. The first thing he imagines is that the floor is covered with lava and he starts yelling and running for safety. Finn is a little annoyed with Jake's persistence and tells Jake to watch as he 'masters reality'. Finn puts his foot on the floor and is shocked when it catches on fire.

Finn comes to the conclusion that everything that Jake imagines becomes real, but is invisible through his eyes. He tells Jake to imagine BMO inventing a better game, but Jake can only manage to think of more lava. Finn becomes frustrated and tells him to imagine turning his imagination off. Jake says that he can't do that, but he says that he can imagine a switch that can shut down his imagination, and places it in their bedroom. He also imagines a lot of obstacles, like traps, ghosts, monsters, poison fountains, hamsters, and cute girls, which all become real. They go to the weapons room to prepare for their journey. Finn grabs a missile, and Jake suggests a Cosmic Gauntlet as well, but Finn indicates that there is a better one on the other side of the room. Just as they try to grab the other gauntlet, Jake imagines a wall blocking the way, and at Finn's accidental suggestion, also imagines an angry troll, which attacks them, but Finn bests him (and his family), jumps through the window out into the knife storm, and hoists himself and Jake into a attic-style part of the Tree Fort, where Jake finds banana candy and juice.

After imagining a steel umbrella over the bridge to protect them from the knife storm, Finn and Jake eventually come to an imaginary riddle master that tries to give them a riddle, but Jake can't think of one. The riddle master gives them a riddle that makes no sense (what is simple, and yet also a riddle?), and Finn states that that riddle sucks, but that is the wrong answer, and the penalty for answering wrong or not answering is "Death... by SNAKES!" Finn kicks the nuclear missile towards the imaginary riddle master, presumably killing him (as screams of agony are heard), but unintentionally causes the invisible snakes to be blown towards them and start biting them. They hurry towards the bedroom because the imaginary toxins are going to kill them, while being accosted by various obstacles imagined by Jake, and then Finn and Jake make it to the imagination off switch. Finn fumbles for a bit looking for it after Jake assures him that nothing will prevent him from getting to the switch, but he imagines an "invisible" monster, meaning that he is invisible even inside Jake's imagination. Jake distracts "Invisibo" while Finn shuts down Jake's imagination with the switch, causing the bite marks and poison to vanish, along with everything else that Jake imagined. However, without his imagination, Jake loses his 'bombastic' personality and starts acting emotionless.

Finn is annoyed because Jake 'sucks' now. Finn tells Jake that he has to bring back the imagination machine, but Jake says that he can't without his imagination, and that it does not matter because the imagination was pointless. Then Finn says that it was "the opposite of all that stuff" and decides to imagine his own switch so that he can turn Jake's imagination on, but his head is empty. So he starts imagining things, mainly the switch, and then, a lyre player shows up and starts singing about Finn's imagination land.

Angered, Finn imagines a penguin and some spaghetti for the imagination lyre player to trip over and fall into. Then a foppish insect named Bellamy Bug shows up and offers Finn a doily imbued with the tears of his daughter, apparently because her boyfriend broke up with her, and Finn gets mad, having stated previously that if there was anything dainty inside his imagination, he would be mad. Then Finn asks the bug how he got in his imagination, and the bug replies "I don't know. You tell me. *giggle*. Perhaps I represent your secret ...desire... to be civilized..." Finn smacks the bug away and turns its arms into a robot arm and a octopus tentacle and then the arms start to beat up the bug.

Then some penguins come and crowd around the bug, and carry it away. Then Finn runs over to the switch that he made, and flips it. Jake seems to have his imagination back, but then a fairy appears and pushes a hyper drive button with her butt, causing Jake's head to grow immensely and making him unable to control his imagination at all, saying "I can imagine everything!" Finn presses the normal button again, and comes out of his imagination unscathed. Jake tells him in horror that he imagined his mom naked.

Then Jake tests his imagination and finds it under control, and the knife storm stopped, meaning they can finally go on an adventure, but Finn says happily that he's had all the adventure he can handle for one day. Then Finn imagines that the floor is lava, and then Jake pretends to melt in it. He says "just kidding.", then Finn laughs, says "good dog", and pets Jake's head.

Major characters

 * Finn
 * Jake

Minor characters

 * BMO
 * Fairy
 * Bellamy Bug
 * Lyre Player
 * Bazooka Goblin
 * Penguins
 * Riddle Master
 * Margaret (mentioned)
 * Snail
 * Wildberry Princess (cameo)

Music

 * Imagination Song

Trivia

 * Confirmed on Pen Ward's Formspring, this episode is his favorite season one episode.
 * While Finn and Jake are in one part of their Tree Fort (after sitting in a bucket using a pulley system), the initials AT are carved into a heart on a wooden beam, possibly referring to the show which they are on. A dagger very similar to Me-Mow's is also in the beam.
 * In the same area of the tree fort, Jake finds some candy. In a box next to him there is a small cookie resembling Pusheen the Cat.
 * The juice boxes Jake find with the candy have a picture of Wildberry Princess on them.
 * When Jake sits up in the fort, there is a picture of Lady Rainicorn.
 * All three of the beings Finn encounters in his imagination seem to do something with their butts: the Lyre Player wiggles his butt when singing, Bellamy Bug waggles his tail, and the fairy hits a button on Jake's Imagination Machine with her behind. This suggests that Finn thinks about butts a lot. Or it is a posibility that Finn was just being stupid in a funny way in that episode, like many others.
 * The cosmic gauntlet Jake suggests Finn takes looks strikingly similar to The Gauntlet of the Hero Billy.
 * In the title card, the storm in the background appears to be precipitating rain, not knives.
 * The only visible and readable word on Finn's to-do list is the word "FLIP".
 * Jake stated that in the bedroom, there would only be "cute girls and hamsters", but when they got to the bedroom, he said "It's just a bunch of cute girls, but they shouldn't bother you", completely forgetting about the hamsters.

Production notes

 * The commercial for this episode is the very first commercial for the series in live action.
 * When it originally aired, this episode was cut into two parts with a commercial break in the middle. This was done so that the end of the episode led directly into the premiere episode of Regular Show, without a commercial in between. The insertion of a commercial break continued for the next couple of weeks, a fact that Frederator Studios was not happy about, based on this blog post.

Errors

 * Jake's eyes appear to be opposite (instead of white in the middle, it's black, vice versa for the edges) many times throughout the episode.
 * At the start of the show before the Knife storm appears, Finn has the to-do list on his arm, but after the Knife storm appears and they come in the tree fort, the to-do list is gone.
 * When Finn steps on the floor and sets his foot on fire, BMO is on the table. However, when the appliances in the living room start to melt, BMO is not seen anywhere on-screen, which most likely is the result of a continuity/animation error.
 * When Finn and Jake go outside after the Knife Storm had cleared up, there are no knives on the ground, which could be the same effect of a regular storm where the water could evaporate, but then again, knives can't evaporate.

Censorship

 * This episode was censored on Cartoon Network Australia. See Censorship of Adventure Time in Australia for more information.