FusionDex

Enamored with keys, Klefvoir collects any discarded ones it finds and attaches them to its body. Trying to pilfer from it will lead to it trapping the would-be thief within its cage-like lower half.

It apparently does not feel the pull of gravity because it supports itself with psychic power. It never lets go of a key that it likes, so people give it the keys to vaults and safes as a way to prevent crime.