Plates is a Stegosaurus. He was Dr. Cockroach's twelfth creature, and his ninth regular creature.
His card winded up in Cambodia. He activated when the Card Capsule fell open on some stone bricks. He then ran off. He battled and defeated Terry along with the Velociraptor Trio, Giga, Crocs, and Totodile before drawing with Stomper. He was later revealed to be a 17 on the Power Scale.
The third copy of the Spike Arrows Move Card was in his Card Capsule, and was activated along with him.
He has never lost a battle, only won and drawn.