Swirlee

Wikipedia: Thagomizer Originally coined by Far Side artist Gary Larson, “thagomizer,” i.e. “the arrangement of four to ten spikes on the tail of particular dinosaurs, like the famous Stegosaurus,” has been adopted as a genuine anatomical term by palaeontological authorities including the Smithsonian Institution. (P.S. Is there a term to describe words invented for humorous or fictional purposes which later achieved mainstream use?)