Devourer

These tall, mummy-like fiends wander the planes, consuming souls in the name of their dark masters, often Orcus.
Devourers hunt humanoids, with the intent of consuming them body and soul. After a devourer brings a target to the brink of death, it pulls the victim's body in and traps the creature within its own ribcage. When the victim expires, it undergoes a horrible transformation, springing forth from the devourer's body to begin its new existence as an Undead servitor of the monster that spawned it. Skeletons, zombies, ghouls and ghasts, and shadows are particularly attracted to the presence of a devourer.