The cloak appears as a black leather cloak that is smooth to the touch. When it is placed on a dead human or demi-human (elf, dwarf, gnome, etc.) the corpse comes back to life but deformed, and maybe special powers at the DM’s discretion.
The cloak only works once on a corpse. The resurrected creature must wear the dark cloak at all times or they will instantly die when it is taken off, never to be resurrected again. If the current occupant of the cloak dies again or takes the cloak off, its powers may be used on another corpse.