D-Rex

D-Rex (so called because its top looks like a T-Rex skull) is the boss of the third section of Sigma's fortress in Mega Man X. Its top and bottom separate, and both try to crush and seriously damage X. Its main weakness is the Boomerang Cutter.

In Mega Man X: Command Mission, the D-Rex is a common, but powerful, enemy that appears in the Vanallia Desert. This D-Rex is a brownish-grey and is more dinosaur-like in appearance. There is also a weaker and more colorful version found at the Tianna Camp called D-Shark.