Some articles on inferius:

Magic In Harry Potter - Dark Arts - Inferius
... An Inferius (plural Inferi) is a corpse controlled through a Dark wizard's spells ... An Inferius is not alive, but a dead body that has been bewitched into acting like a puppet for the witch or wizard this manifests itself as a white mist in the controlled corpse's eyes ... enough by the magical world that impersonating an Inferius (as Mundungus Fletcher does in Half-Blood Prince) is an offence worthy of imprisonment in Azkaban ...