Little Brother

Synopsis
Shelby accidentally gains a new brother, who he inspires to become a great hero.

Plot
The episode begins with the night view of treefort. The view goes inside the treefort, and Jake is seen to be starting a metronome. He starts this and follows its oscilation to play his viola perfectly. As soon as he starts to play, someone is heard shouting inside his viola which startles him. As he sees inside, there seems to be a bug party going inside his viola, and it's also seen that Shelby is hosting it. Everyone is having fun, and Shelby asks a Dancing Bug to 'shake it'. At first he was strating to disagree, but then he agrees and starts to dance, which makes everyone awe-struck. Everyone gathers round the bug, and a scorpion starts to compliment it by saying it was the best bug in this party. This makes Shelby jealous, and he says he can do it. The scorpion asks what will he do, to which he replies he will do parkour. He performs his parkour by jumping on a pole, then on the roof, but he is pulled down because he could not hold for long. When he fell, he says that he is quite hurt, and finds that his lower part of body is severed by a string in mid-air when he fell.

Shelby falls unconscious and the scene changes to him waking after a long time. He is astonished as his lower part starts to move. Shelby asks who he is, to which the creature could only blow a rasp. Shelby finds a note in his lap, which explains that the severing of his lower part meant that he has a new brother now, and his name was decided to be Butty Butterson. But Shelby says that he will call his brother Kent for short.

Outside the viola, Jake is seen to be sleeping soundly, and Shelby calls out to him. He wakes up and is confused to see Shelby's severed butt. Shelby explains that since his lower part got severed he now has a little brother whom he will call Kent. Then Kent speaks his first words, which is,"I'm Kent" and this startles Shelby. Jake is surprised that he could chop off a worm to get two, and called that he thought it was a myth. Shelby says myth is his power. He then says to Jake to help him how to raise a brother. Jake says to give him something sharp to fight off bad guys and says sometimes he might also have to help, referring to his and Finn's adventures. Shelby agrees, and starts to go and Kent goes away and before he goes, he says to Jake that someday, he will be his food.

After this Shelby offers Kent a sword, and Kent is happy with it. He sprouts two arms and picks the sword. This makes Shelby surprised, and asks how he'd do it, to which Kent says he did not know. Shelby then explains that since he is the little brother, he should fight off bad guys... or girls. After this he sends him. This time, Kent sprouts legs and runs away. Shelby tries to sprout legs like him, but could not. Kent is then seen to be walking beneath the treefort and as he walks, he comes across a rat wearing a crown who is chewing off the root of the treefort. He starts to go after the rat with his sword, because he was a bad guy, and startles the rat. The rat runs away in a nearby hole and Kent follows it. Kent says it to get back and but it runs away into dark. Kent is suddenly confronted by some pair of white eyes, and a big pair of red eyes, which flashes and the scene changes.

It is then seen that Kent was bruised and is sleeping in a bed. Near him, a plant creature greets him when he came to consciousness. Kent is startled and asks who he is, to which the it laughs. Kent asks where he is, and another creature comes in. The new one is happy and offers him a dewdrop do drink, which makes Kent free from his bruises. The one who healed Kent introduces itself as Leafbeard. He then explains that the 'RatKing' has made near the roots of the tree, at which they currently reside. He asks him to be careful. Kent is confused and says that he doesn't know what or who a Rat King is. Leafbeard then comes to the conclusion that Kent is not from the roots of the treefort. Leafbeard tells that Rat King is the one who is destroying their habitat, which is the tree's roots. Kent comes to conclusion that the Rat King is bad. He asks for his sword, but Leafbeard says it was broken to shards when they found him. He asks Leafbeard where he can find a new sword, and the creature who greeted Kent first introduced herself as the blacksmith, and only some certain ingredients are needed for a new sword. She sends Kent to bring these.

The first ingredient is to find an unbreakable ore. She tells Kent to follow the sound of the singing crystal to find it. Kent is going on his journey and when he reaches, a rat inside a emerald - type forcefield greets him. Kent asks for the unbreakable ore. The rat instead offers him a lot of emeralds, and that he could be rich with it for life, but Kent refuses. The rat is impressed, telling that wealth cannot tempt him so he gives him the ore, which is found out to be a soda bottle cap. He continues with his journey and suddenly, a sword almost was going to kill him but he bent down.

The sword came from a swordsman rat. Kent asks whether he has the mystic earth. The rat tells him to consider in marrying one of his daughters. Kent refuses it, and the rat tells he has passed his test and offers him the mystic earth.

The third item was the sacred flame. He continues and is greeted by a ninja rat. He tells him to consider drinking a water, which he produces from breaking a wall nearby, which will make him immortal, but Kent refuses and the ninja offers him the sacred fire, which is a firefly. With these, Kent returns and the blacksmith makes him a perfect sword. He then fells happy, and when he was going out, he saw the Rat King on his way and chases it to its lair. The Rat King then speaks to him asking why he was here. Kent replies he was here to fight him. He goes through the body of his enemy, which is found out to be a body made by many rats. The Rat King says that he should join him and he will become a King, and live like a God. Kent refuses and goes to kill it by getting near its head.

He then takes his sword and severes the teeth of the rat. The scene changes to Shelby seeing both Finn and Jake being happy. Shelby starts to sing about his brother. By and by, Kent's voice comes and they both start to sing at same time. After this, Shelby and Kent becomes happy, but then Shelby writes about how his brother, due to his ingestion of the dewdrop of the underworld, needs to be returned there. Maybe he was going for the offers the rats made, but he just knew that due to the break of the Rat King's curse, the willow tree will bloom for the first time The scene changes to the willow tree, which is bloomed with pink blossoms and the episode ends.

Characters
Main Characters
 * Shelby
 * Kent
 * Rat King

Minor Characters

 * Finn (non-speaking cameo)
 * Jake
 * Pincer Beetle
 * Simon
 * Leafbeard
 * Dewdrops
 * Snail

Songs

 * "Little Brothers"

Trivia

 * Shelby's brother is based on the concept that earthworms can have two living segments when split in two.
 * This episode is Finn's shortest appearance in the series by far.
 * Kent can walk, despite being a worm, but Shelby can not.
 * This is the first time the Tree Fort has been seen in bloom.
 * The concept of rats being ruled by a rat king inside the treehouse was first seen in a Fionna and Cake comic by Natasha Allegri.
 * Kent somewhat resembles a Scientific Parasite.

Cultural references

 * Kent's return to the underground due to partaking the dew is similar to the myth of Persephone, who must return to Hades during the winter due to eating three or four pomegranate seeds from the underworld.
 * This episode closely follows the structure of a Monomyth.
 * The Rat King concept was possibly based on a background character in Alan Moore's .
 * The Sacred Flame might be a reference to the Castlevania and/or Zelda series
 * A rat king is where a bunch of rats are intertwined by their tails.
 * The making of the sword can be a reference to a Legend of Zelda The Minish Cap where the hero must rebuild a broken sword by finding various elements.

Episode connections

 * Pincer Beetle is seen doing the dance move Jake taught him in "Power Animal."
 * He is also dancing to the same song.
 * The premise of this episode is similar to that of the scrapped episode "Brothers in Insomnia," the only change being Shelby and his brother being the main focus of the episode instead of Finn and Jake.

Production notes

 * This is the first episode boarded by Madeleine Flores.