A giant crayfish looks like a giant lobster with a sharp snout and eyes on movable, flickering stalks. Two large claws extend from its thorax in front of four smaller pairs of spindly walking legs. Its exoskeleton is dark brown.

Monstrous crayfish are freshwater creatures that dwell on the bottoms of seas, lakes, ponds, and other shallow water. They are predators and scavengers that exist on a diet of decaying flesh from dead fish, algae, snails, worms, and other animals, including swimmers who venture too close to the monstrous crayfish's lair.

These giant crayfish make their homes under rocks or in underwater tunnels that they dig. Their flooded tunnels extend over long distances and always include a "chimney" through which the monstrous crayfish can enter and exit its home via dry ground. These exits have been found as far as 100 feet inland from the lake shore or riverbank.