Size and Weight:
Carnotaurus is one of those dinosaurs that looks like it didn't come out of the oven quite right: its arms were small and stubby enough to make those of Tyrannosaurus Rex seem gigantic by comparison, and the thick, stubby horns over its eyes were too small to be of much use, except perhaps as a sexually selected characteristic. A new study has shown that the tail of Carnotaurus was unusually straight and muscular, implying that this dinosaur was able to reach very respectable running speeds in pursuit of prey. (To make up for its various weirdnesses, though, you have to admit that Carnotaurus had a cool name, Greek for "meat-eating bull.") Another recent study concludes that Carnotaurus possessed an unusually thick neck, which may (or may not) have had something to do with its stunted arms.
Carnotaurus was easily distinguishable from the other large theropods of the late Cretaceous period, which may account for much of its popularity (for example, it's the featured carnivorous dinosaur in the Steven Spielberg TV series Terra Nova). To date, only one species of this fierce predator has been discovered; maybe the other dinosaurs laughed this unfortunate meat-eater out of the evolutionary tree!