The spinosaurus is more than just one of the largest carnivorous dinosaurs-it's also one of the most unusual in appearance, with a large, sail-like fin running along its spine. Often quite colorful, this sail allows the spinosaurus to attract mates, aids in swimming, and makes it appear to be even larger than it actually is. A swimming spinosaurus can also use the sail as part of a unique means of staggering prey by slapping the water with it to make a crushing wave.