Hideous is a revolting, gruesome, pernicious, and disagreeable Psymonster who likes everything that is repulsive, disgusting, unsavory, odious, foul, gross, repugnant, horrendous, poisonous, distasteful, objectionable, loathsome, unpleasant, horrible, awful, icky, terrible, rebarbative, nauseating, grotesque, putrid, vile, rotten, and offensive. He loves having bad dreams, doing nasty things, and tasting extremely poisonous drinks. He loves taking long walks through the landfill of the Psymonster World, smelling the odor of stinky things, and eating garbage everywhere in the Psymonster World. He loves ugliness, gross things, and noticeably unpleasant smells. Because of all that, Hideous tends to come off as just a little bit different. Any Psymonsters don't always understand his point of view, or his sense of style, or his habit of suddenly appearing behind them in the closet when they don't know that he is in the room. But he can't help himself being so ugly, noxious, horrifying, unattractive, and grotesque, it is just the way he is.
He is a big, obese black garbage monster with yellow eyes, purple arms and legs, sharp teeth, a dark blue mouth with a blue tongue, and a gray garbage can suit.
- The name "Hideous" means ugly or disgusting to look at.
- Hideous is one of the six Psymonsters who have elliptical eyes (the other five are Dragonster, Snakegrowth, Deceased, Candyip, and Barbeetle).