Short: $adjective$ reaper (with adjective selected from brooding and silent)
This is a reaper - a variant of the zombie form that is notable for its cool, calm demeanour except when pursuing meat. At that point, it opens its mouth and emits a powerful, mind-bending screech that scrambles the ability of the human mind to cope. Despite the rotting flesh that hangs from its bony frame, it is unusually large and bulky.
Skills: quite unskilled zombie