Physically, Whim resembles a traditional drawing of Satan with a crescent moon-shaped head and bright blue skin. Whim demonstrates shape-shifting abilities that work well with his sadistic fondness for warping reality and transforming residents. However, it is shown that the devil physique is only a shell for what appears to be its true form, a worm-like entity that can possess anyone and anything, including the protagonist Frank, into a hideous and hallucination-esque contortion.
Whim lives beneath the surface of the Unifactor in a kind of physical Hell, further befitting its Satanic image and mannerisms. It is implied that Whim is a kind of Lovecraftian horror as well-especially considering that Whim devours the souls of various cosmic horrors encountered in the comic. This would also explain many of Whim's powers and its fondness for inducing what would otherwise be maddening effects on those unfortunate enough to cross paths with it. Or those its seeks out.
MannerismsAs a chaotic entity, Whim emerges and appears out of nowhere to warp reality and residents against their will (in a manner similar to Discord albeit on a bigger and far more grotesque scale). Using an egg beater-like device, Whim can reshape the surroundings and create hallucination-like effects (such as altering colors). As seen in one comic story and its subsequent adaptation in the Visions of Frank short animation series, Whim antagonizes Frank further once his true worm-like self escapes the body attacked by Frank's dog-like pet Pupshaw. Going in through Frank's tail, Whim forces Frank to undergo painful transformations (going by Frank's horrified/pained expressions in the process) until Pupshaw forces Whim out. Nevertheless, Whim flees.
In other cases, Whim can be quite petty with its sadism. In one page of the comic, Whim somehow convinces Frank to allow it to tie Frank to a tree. Then it just strikes Frank with an oversized claw-hand, as if to mock Frank for foolishly allowing it to do this.