Death's-head Hawk Moth

Death's-head Hawk Moth (also death's-head hawkmoth) was a name used to refer to any one of three species of moth characterised by thorax markings that formed a shape reminiscent of a human skull.

The final step in preparing the Animagus potion involved adding a Death's-head Hawk Moth chrysalis to the file containing the potion and leaving it in a dark, undisturbed location until a lightning storm.