This animal sounds surprisingly like a member of the stegosaur tribe. As far as we know, stegosaurs lived around 150 million years ago. There is no indication in the fossil record that a population survived, but we must always bear the limitations of the fossil record in mind. The stegosaur had a tiny brain. The idea that they harbored a second brain in their tails has now been shown to be false. They had plates on their backs and spikes on their tails. It is possible that, at least sometimes, the plates were in two rows. They could not be used as weapons due to their fragility. It is thought, on the other hand, that their tail-spikes could land a serious blow. They were herbivores and lived in North America, Africa and Asia (where they possibly originated).