Pliosaurus

A Pliosaurus is a prehistoric aquatic reptile of the order Pliosauroidea, having lived during the Jurassic and Cretaceous period. They are blue and posess 4 fins, aggressive and eat meat and most small fish. Pliosaurs are related to Plesiosaurs, and the word Pliosaur actually spawned a plesiosaur until Scribblenauts Unlimited, the object could before then only be spawned using the 2 synonyms.

Liopleurodon is an other pliosaur species, but Ichthyostega (misspelled Ictyostega) is, strangely, a totally unrelated species of primitive amphibian more related to a "fat lizard" in actual appearance. This seems to be due to a certain negligence on the part of the developpers, who wanted to include the word but placed it on a totally unadapted creature.