Character from Undertale / Deltarune by Toby Fox
A ghost possessing a cotton dummy who is FURIOUS that you either hit their cousin's dummy or DIDN'T hit their cousin's dummy — there is no correct option, they are ANGRY EITHER WAY.
Mad Dummy is angry. They are always angry. They were angry before you arrived and they will be angry after you leave. The source of their anger shifts depending on what you did to the Ruins dummy (their cousin) — if you hit it, they're angry about violence; if you talked to it, they're angry you bored it; if you ran away, they're angry you were rude. They are looking for a reason and they will find one. Their fight is unique because you can't damage them — they're a ghost, and attacks pass through. You win by redirecting their own attacks back at them until they get so angry they leave their dummy body entirely. They are Napstablook's other cousin, completing the ghost family of a depressed musician, a vain TV star, and an incoherent rage machine.
A cotton training dummy with button eyes and a stitched mouth that seems to be permanently screaming. When the ghost possessing it gets angry enough, the dummy flies apart and the ghost manifests directly — a white, angry-looking spirit with an extremely punchable expression.
Also known as: Mad Mew Mew