Eater of the Dumbs

This unique creature can be found roaming Avernus, the first layer of Baator. On rock-strewn Avernus, visitors can often see weird faces and painful-looking shapes in the rocks and mountains, and at least some of them actually are petitioners.

The Eater of the Dumbs evolved from such petitioners. A pit fiend decided to test what would happen if all the captured souls would melt together. (Despite the fact that the pit fiend had been demoted afterwards, Bel and his servants allow the Eater to roam the layer, as they were probably curious themselves as to what would develop there).

From a distance, the Eater just looks like a normal, giant rock. If you come near enough, though, you can hear slight voices from inside. There's a cavern entrance, and from within it moans and sighs can be heard.

Very soon, these moans change into cries for help, for example: "Heeeeelp meeee... pleaaaase... I'm trapped here... I'm .. dyiinng... [deep moaning] pleeease.. heeelp.." A person who enters the caverns finds they're very dark, and somehow even magical light doesn't work here. The caverns seem to lead down very far, and the voices seem to come from always farther below. After a minute or two, the chill of the caverns extracts one hit point per round from the characters inside.

Actually, the Eater of the Dumbs takes these hit points. The victims can regenerate them normally, but the creature gains a bit more power permanently from every hit point drained. Those who die inside the caverns suffer a really evil fate: One of the petitioners' souls who have melted into the Eater frees itself and takes over the body of the victim. This way, the victim raises again suddenly (though it only has one hit point then), but is now infused with the soul of a Lawful Evil creature.

There is no known way to hurt or even destroy the Eater (though it surely wouldn't be a problem for Bel). The best way to overcome this obstacle is to simply avoid it. Thus, this creature is actually a very good metaphor for Baator itself.