The spiky end of a Stegosaurus tail is one of the most famous bits of any dinosaur. Four big sharp spikes, each up to 3 feet long, swinging at the back of a tail like a medieval mace. They were the Stegosaurus’s main defense against predators.
For about a hundred years, scientists didn’t actually have a name for that arrangement of spikes. Then in 1982, the cartoonist Gary Larson drew a Far Side comic showing cavemen at a chalkboard with a labeled Stegosaurus, captioning the tail “the thagomizer - after the late Thag Simmons.” It was a joke.
Paleontologists thought it was hilarious. They started using “thagomizer” in talks. By the 2000s, it was being used in real scientific papers. Today it’s the standard term for the spiked tail of stegosaurs - a fake word that became real.
