Cephalaspis was a prehistoric fish from the Ordovician period. It was an easy prey for the predators and super predators of its time, like the sea scorpions or even the Giant Orthocone.
Walking with MonstersEdit
Cephalaspis appeared in the first episode of Walking with Monsters. It was shown as a constant prey for the Brontoscorpio, a prehistoric sea scorpion. However, they are also shown as the most intelligent creatures from the Ordovician period and they were probably the first beings to have memory, in addition to having sensors that detected the danger. All those characteristics gave them advantages over their predators.
Cephalaspis is shown evolving into Hynerpeton, but that process of evolution isn't utterly correct.