Carnotaurus

Carnotaurus ("meat[-eating] bull"), was one of the most bizarre yet dangerous meat-eating dinosaurs ever found. Its skull was short, with spiked armor on the top and a pair of knobby horns over its small eyes. The neck and shoulder blades were well developed, but the arms were incredibly short, with forearms so shrunken they were practically just wrists; not even Tyrannosaurus Rex had such small arms.

With its small skull, Carnotaurus might not have been able to attack big plant-eaters, but it was probably fast due to its long and powerfully-built legs and could have easily chased down smaller, more agile prey. In fact research as indicated that despite Carnotaurus had a small head the jaws were able to open very widely a part from other theropod dinosaurs in order to catch prey.

The horns of Carnotaurus look something like those of a bull - and like a bull, it may have used them in contests with others of its own species. In this way, two Carnotaurus could test each other's strength without either of them seriously injuring the other.

More real-life information: Carnotaurus at Wikipedia.

Appearance
A Carnotaurus holds a height of 3.5 meters (10-12 feet), length of 6 - 9 meters, and weight of 1 ton.