Megalograptus means "Great Graptolite," which refers to the fact that the first Megalograptus fossils were mistaken for graptolites (prehistoric colonial animals). We now know that Megalograptus was a eurypterid that looked superficially similar to a scorpion. It was slightly over a meter in length, with two massive appendages extending from beneath its head. These two appendages were covered with forward-facing spines, which may have been used to trap prey in front of it front of it to be eaten. Its tail was long and forked at the end, but it was not a stinger like those seen in modern scorpions. Megalograptus lived in coral reef environments of the Ordovician Period. Its spiny pincers helped it eat fish and other soft-bodied creatures, but its ability to eat tough trilobites is questionable. In addition to prey items, Megalograptus lived alonside crinoids, sponges, ammonites, and other species of eurypterids. It likely had no predators as adults due to its hard exoskeleton, but may have made a tasty snack when it was molting and vulnerable.