A game mode that allows you to keep playing after death. There are two ways this could go:

• Continue playing as the monster who killed you. This game mode would likely be non-scoring, and your actual character’s death would be written out in the normal manner.
• Continue playing as your own corpse. In this mode, you are effectively a blind, deaf, and sessile monster who can take no actions other than resting. The game finally ends when your corpse rots away. This is mainly interesting combined with an implementation where allies can zap your corpse with undead turning to resurrect you; if they do so before you rot away, then you can keep playing. It’s not clear what would happen if you are petrified instead; a statue can survive indefinitely, and the odds of a pet being able to stone-to-flesh your statue are low but not zero, so possibly the criteria should instead be “you die when there are no more pets on the level”. This still has a problem in that some pets could survive indefinitely, though.