Atropal

Of the many deities and demigods across the planes, only a fraction of real knowledge is held. These beings, unknowably powerful, defy rational thought; they live indefinitely, apparently drawing some power from the faithful acts of their followers.

Knowledge of the creation and destruction of godly beings is thus incredibly hard to come by. One story, however, is sometimes whispered of by the eldest and most knowledgeable archmages: it is said that sometimes, when a god comes into being, some fault or flaw corrupts its manifestation and the god perishes in the instant it is born. These stillborn gods, still powerful in their own right, instantly rise as gigantic undead beings called Atropals. An abomination in the truest sense of the word, the rise of an Atropal dooms worlds.

This is the first creature we've done from the Epic Level Handbook, a fun volume that contains everything you need to make an adventure for characters at 20th level or higher (at level 20 characters pretty much become demigod superheroes). All the creatures in the ELH are really imaginative and cool, and most of them stats that would make a 5th level paladin cringe. The above creature is surrounded by a 30-foot aura that kills most creatures outright then resurrects them as undead minions a few turns later. Yipes!

and yes, it's pretty much an aborted god-fetus. sorry!