Anomalocaris

Anomalocaris has been described as the first ever large predatory animal ever to evolve. It is generally agreed-upon that it is an ancient stem-group relative of the arthropods. Its fossil history was a puzzling one; its great appendages were the first to be excavated; under the impression that they're entirely distinct animals, this is how Anomalocaris got its name (it was thought to be a crustacean since then). Then its pineapple-ring mouth was uncovered, then branded off as Peytoia, a cnidarian. Its body was found, under the distinction of Laggania, a sponge. Then in 1985, a paper was published dictating that all three fossil finds were in fact, part of the same animal, and due to naming regulations, Anomalocaris became its official name, with Peytoia and Laggania being retconned to sister taxa synonymous with each other. In Walking With Monsters, the species described is A. saron of the Chengjiang biota. Its first appearance showed it feasting on a trilobite of dubious affinity, then there was a close-up of one of its eyes - with the narrator explaining how and why animals evolved eyes, then it clashed great appendages with another Anomalocaris. When the loser retreated, its wounds were ripe for a ravenous swarm of Haikouichthys to exploit.