The Rock Monsters are the enemy of the Power Miners (Duke, Brains, Rex, and Doc). They appear in most of the Power Miners sets. They are made of different coloured rock and crystals. There are five different kinds of Rock Monster. The rock monsters are Meltrox, Boulderax, Glaciator, Sulfurix, and Firox. Meltroxes are red, and are apparently always angry. The yellow ones, Sulfurixes, are more intelligent and can melt tunnels through solid rock. Apparently, all of the Rock Monsters are afraid of the blue Glaciators. The Glaciators are shown to have ice powers (as seen in the trailer for the game Rock Rocket). The green ones are Boulderaxes which are strong, slow, but not intelligent, and often attempt to destroy the Power Miners' vehicles. The orange ones are Firoxes which are extremely fast