Out on the Late Jurassic savannas, an Allosaurus fragilis attacks a Stegosaurus ungulatus. If the allosaur is going to bring the seven-ton plant-eater down, it must confront its prey’s formidable tail spikes (collectively referred to as a thagomizer, after the late Thag Simmons).
In fact, we have fossil evidence from a wound marked on an allosaur’s pubic bone that such confrontations between the Allosaurus and Stegosaurus actually would have taken place. Apparently, a stegosaur’s tail spike had struck the allosaur in the crotch, leaving behind an injury that became infected and killed the predator.