Tyrannosaurus is a small, white mouse, with a long hairless tail, red eyes, and a cheerful look on its face.[1]Most of the time it stands on his rear legs, keeping its front legs raised in a standard mouse pose somewhat resembling a Tyrannosaurus Rex, which probably gave it the name.Over the last two years, it has grown to several times its original size, going from being able to fit in Iceburg's pocket to about the size of its master's head.After the two-year timeskip it is seen wearing a collar as well as a small vertically striped suit.PersonalityTyrannosaurus spends most of its time lying in Iceburg's pocket and squeaking happily when Iceburg caresses him.[2]It is apparently very loyal and attached to Iceburg, as it is always seen with him. During the fire at Galley-La Company's headquarters, instead of running away, it remained by its master's side, trying to wake him up with squeaks in order to save him.