Gastonia, a mid-sized ankylosaur, is one of the spiniest dinosaurs ever. This herbivore was around 13-16 feet long and weighed over 1,500 pounds. The spikes that covered it's body could be up to a foot long. It's tail was designed like a chainsaw and would have been the perfect deterrent against predators like Utahraptor. Gastonia lived in North America about 130 million years ago.