Slaargh

Slaarghs are anomalous enemies that may appear in some copies of Super Mario 64. They appear as worms with long, pointy mouths and small red circles on their cheeks. Their tails are not visible as they are universally submerged in some kind of fluid.

Behavior
Slaarghs attack by spewing acid or poison, which reportedly sticks on floors for a time before vanishing. Staying in the acid damages Mario, possibly through applying a persistent poison effect or simply passively dealing damage, similarly to the smog to Hazy Maze Cave. In some reports, they may periodically submerge in the water. Shortly before firing, they open their mouth and stop moving, becoming vulnerable. They are usually defeated by throwing projectiles at them, such as boxes or Bob-Ombs.

Enemy Discoloring
Red Slaarghs supposedly appear in lava levels, and spit lava instead of acid. The difference is that the lava sends Mario jumping instead of just hurting him.

Blue Slaarghs spit water, which does not leave a hazardous spot on the floor.