Haraevor

Haraevors were a type of dragonspawn were capable of traveling through and emerging from from solid stone of Toril.

Description
The reptilian bests looked like enormous crocodiles with four heads.

Behavior
Haraevors primarily traveled underground, moving through stone and earth.

Combat
These creatures traveled through stone to gain position on their foes, then attacked with each of its four heads. They had enough self-preservation to flee underground when they were in grave danger.

Ecology
It was believed that the existence of haraevors was a result of breeding between earth titans and dragons, most likely gray dragons.

History
The Order of the Dawn book, Primordials and their Servitors, referred to haraevors as "crashing death from earth".