Cave Worms

The Cave Worm of Mars is truely a disgusting creature. This absolutely featureless worm would wait in the dark mine, giving off a light glow to attract prey. Once it spots prey, it shoots off spikes or tries to grab the victim with its tentacles to melt it with acid. However, they are pretty harmless if the adventurer is careful enough and kills them from afar. Projectile weapons work best against it.

As mentioned, found in dark caves.

Lore
''Unlike its distant relative, the extinct canal, cave worms are quite real and quite deadly. These glowing shelled cave dwellers can grow to lengths up to ten feet, but a spitting attack makes them a threat at far greater distances. Once prey comes within reach, a cave worm uses grasping tentacles to squeeze the life from its victims. Like many Martian creatures, the cave worm secretes a burning acid through its skin. Victims are, in essence, rendered down to liquid which the mouthless worm absorbs through its skin.''

- from "Mysteries of the Red Planet", Martian Dreams