Damu

Damu was a desert planet, its oceans having dried up billions of years ago. Due to the unusual composition of the planet, boiling hot mud flowed throughout the planet's crust, blasting its way to the surface in dangerous explosions. The planet was riddled with caves (actually blowholes) that had been excavated by the violent mud flows, some of which lacked oxygen. Despite the conditions of the planet, it had a breathable atmosphere and was home to such life as The Damirarians and The Reptilias Beasts, but was otherwise unsuitable for habitation by humans. (TV: The Monsters)