Inktober Monstrosities: R for Rock Reptile

You'd think finding a good monster for the letter R would be easy, it being the fourth most frequently used consonant in the alphabet, but as it turns out there were actually few good candidates on R. The final choice actually fell on this critter, the Rock Reptile, which again you'd be forgiven if you've never heard about. It only appeared in the Monster Manual II for first edition AD&D, and then a third party monster book for third edition (Sword & Sorcery - Tome of Horrors from Necromancer Games), and that's it.

They are described as horse sized lizards, living underground, with lumpy, warty hide and chameleon like powers.