''The reverently named Earth Leviathan, of the family Piscicolidae, is one of the largest invertebrates found around the Thistle Nebula. None have been captured, so not much is known of their biology.

Just in time for summer, the megalodon—the ancient, city bus-sized shark known as the “Megatooth”—has reared its ravenous snout. While the oceans are now safe from the Megatooth, which went extinct an ...