5 Legger

The 5 Legger was a type of creature, so named because of its five legs, two set on its upper body like arms, and three arranged around its pelvis like a tripod, with three fingers on each food. In addition, the creature had an elongated skull and horns similar to that of a triceratops.

At some point in Hogwarts history, someone had reason to hide one of these creatures in the Room of Requirement, choosing a large cupboard to place its cage in. Whether it was alive at the time is unclear, but by 1997, it had degraded to the point of being a bare skeleton. Harry Potter, seeking to hide the Half-Blood Prince's copy of Advanced Potion-Making, chose the same cupboard, stashing it behind this creature's cage. It was presumably destroyed around a year later when Vincent Crabbe ignited most of the Room of Requirement with Fiendfyre.