In World of Warcraft, there are certain creatures that you have to kill and in order to get the reward you must bring back evidence of their demise - sometimes a body part, sometimes a distinctive possession. If your character was a quest mob and someone had decided they needed to die, what would they drop?
Live
Cassius Cordo (Obsidian Arcana) - Either his bag full of equipment and notes or his power stone.
Carrack Libra (Far Shores) - A flayed fragment of his face covered in woad markings.
Mehendrie Solon (Far Shores {KIA}) - His House Dark banner (already taken).
Andodus (Old Far Shores {KIA}) - His pipe or his pouch full of leaves and dirt.
Table-top
Mikere (In Nomine) - A feather from his wings (soul death) or one of his Role items, like a rolex watch (corporeal death).
Benjamin Ravish (M&M) - His head. That's the only way you'll know that the bastard is dead. Seriously, with this guy 'missing presumed dead' just wouldn't cut it.
Anton 'Soap' Lictfuss (WFRP) - His 'fuckoff big' knives.