Mordenkainen's Tome of Foes introduced the Dybbuk, a neat CR 4 Medium fiend (demon) with a peculiar ability:
Possess Corpse (Recharge 6). The dybbuk disappears into an intact corpse it can see within 5 feet of it. The corpse must be Large or smaller and be that of a beast or a humanoid. The dybbuk is now effectively the possessed creature.
What does "an intact corpse" mean in that context? A humanoid turned into pulp by a giant is probably invalid, but is a humanoid killed by a dagger in the back intact enough?