When Gumball's jar of disgusting things gets thrown in the microwave, a small creature is born and Gumball and Darwin raise him as their own — until it starts to grow and begins devouring the rest of the family and attack the neighborhood.
Tropes:
- The Blind Leading the Blind: Darwin and Gumball want parenting advice, so they ask Richard about taking care of Kenneth. Richard thinks of it more like training a dog, and thinks he's asserting his dominance by sitting calmly while Kenneth eats him.
- Creating Life Is Unforeseen: One wouldn't exactly think heating a bunch of gross crap in a microwave would create a new form of life.
- A Day in the Limelight: For Kenneth.
- Downer Ending: Kenneth grows into a full-on Kaiju as Gumball laments that it was maybe best for them to just kill him when he was still harmless.
- Eye Scream: The first thing Kenneth tries to eat is Darwin's eyeball.Darwin: (before being bit) Ah, he's kinda got my eyes.
- Feed It a Bomb: Rather than a bomb, Kenneth is defeated by feeding him a hose, then turning it on to build a tremendous amount of water pressure, but the effect is very similar (but less harmless to those inside). This ends up reducing Kenneth to the same size as when he was born.
- Here We Go Again!: Kenneth spits everything and everyone up and, reducing him to his original size, and Gumball insists he can keep him under control. Gilligan Cut to an even bigger Kenneth knocking helicopters out of the sky.
- I Meant to Do That: Gumball is knocked into the valve for the hose Kenneth swallowed, and when this saves everyone he pretends it was his idea.
- Parents for a Day: Darwin and Gumball accidentally create Kenneth, and it calls Gumball "mama", which they take means Darwin is the dad. They take care of it until it starts eating everyone, and Gumball alternates between being concerned and terrified of his "son".
- Screw This, I'm Outta Here: When Gumball tells Darwin that he's the father of the slimy microwave creature, Darwin tries to leave, even using the old "I'm going out for cigarettes" (changed to "...buy some stuff... at the shop?") excuse associated with deadbeat fathers about to abandon their families. He's even wearing a fedora and carrying a suitcase!
- Swallowed Whole: Kenneth eats people and animals whole, and they can even show themselves to the outside by pushing their faces again his stomach.
