The creatures are minor characters in The Amazing World of Gumball. They are creepy and hostile monsters which inhabit the Forest of Doom. They first appear in "The Picnic," when they try to harm and scare Gumball and Darwin when the two get lost in the Forest of Doom.
Each of the creatures is a twisted, monstrous version or hybrid of an animal. Most of the creatures are either very monstrous or at least have malevolent and sinister intentions.
- Evil tree: A living tree with a face, which acts happy and inanimate around Darwin, but shows a malevolent expression and intention towards Darwin whenever he is not looking.
- Evil squirrels: A duo of demonic, vicious and mutated-looking squirrels which Gumball and Darwin pass by in the Forest. Though Darwin and Gumball do not notice anything odd about the squirrels, after the two are gone, the squirrels conspire to devour Gumball and Darwin's carcasses.
- Deer-chicken hybrid: A hideous and monstrous creature with a deer-like body and a hideous chicken-like head. A hungry Gumball and Darwin see this creature at a distance and, mistaking it for a real deer, try to ambush and eat it. But upon seeing what the creature really was, the two are scared into apologizing and backing off.
- Caterpillar: A colorful, one-eyed caterpillar, and apparently a harmless and benevolent creature of the Forest of Doom. Gumball and Darwin catch the caterpillar to eat it, but are moved into letting it go by the creature's cuteness and how it has feelings, as well as so that it could enjoy life, only for the caterpillar to be captured by a bigger monster and eaten by another monster seconds later.
- Fish-bird creature: A fish-like bird which eats the caterpillar creature, only to then itself be eaten by another, larger monster.
- Tentacle predator: A large, predatory monster with a koala-like face with whiskers and octopus-like tentacles. It first appeared when it eats the fish-bird creature, only to then be itself ambushed and eaten by another monster. The tentacle monster shortly after reappears with the other giant monsters to terrorize a defenseless Gumball, but was frightened off when Darwin stands up against the monsters for his brother.
- Gryphon predator: A giant, one-eyed, predatory monster resembling a gryphon. It first appeared when it eats the tentacle predator, only to then be itself ambushed and eaten by another monster. The gryphon creature shortly after reappeared with the other giant monsters to terrorize a defenseless Gumball, but is frightened off when Darwin stands up against the monsters for his brother.
- Minotaur predator: A massive, one-eyed, minotaur-like predator with a bear-like body and moose-like antlers. It appeared when it eats the gryphon predator, and then goes after Gumball and Darwin. However, the minotaur predator and the other monsters with it are frightened off when Darwin stands up against the monsters for his brother.
- "The Kiss": (debut) The fish-bird hybrid appears flying in Darwin's happy place.
- "The Picnic": Their first major role. They try to kill Gumball and Darwin throughout the episode.
- "The Voice": The deer-chicken hybrid messages Gumball and Darwin on Elmore Plus, and they block him.
- "The World": Several of them sing at the beginning of the episode, and the minotaur and evil squirrel appear later.
- "The Name": Some of them appear in Gumball's subconscious.
- "The Shell" (mentioned)
- "The Question": Several of them sing "Eat or Be Eaten."