T-rex Coloring Pages: Tyrannosaurus Rex, was a massive dinosaur with short arms, sharp teeth, and a large head. It had a long, powerful tail and stood on two legs. T-rex had a thick, scaly skin and was covered in a layer of feathers, giving it a slightly fluffy appearance. Its most iconic feature was its large, gaping jaw full of razor-sharp teeth, which it used to hunt and eat other dinosaurs. T-rex had a bulky body and could grow up to 40 feet in length, making it one of the largest carnivorous dinosaurs to ever roam the Earth.