D-Rex

D-Rex is the boss of the third section of Sigma Palace in Mega Man X. It was supposed to be a large Mechaniloid based on the T-Rex (hence the name), but by the time the fortress was discovered by Zero, only the head was completed, forcing Sigma to convert it into a tank.

Its top can detach from the bottom, hovering in the air, and both try to crush and seriously damage X. When either section collides with a wall, it can daze X and knock him off. Both sections can also charge up massive electron spheres that inflict devastating damage. Its main weakness is the Boomerang Cutter.

D-Rex (Command Mission)
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. D-Rex attacks with shots, Heterostorm and releases explosive miniatures called Mini Rex. If its mouth is damaged, it will be unable to release miniatures.

Run away in his third turn onwards after being damaged by 11 C-type attacks. Trickstar and Stealth Mode take damage of Mini Rex.

D-Shark
D-Shark is a weaker and more colorful version of D-Rex found at the Tianna Camp in Mega Man X: Command Mission. D-Shark attacks with Ultra Blizzard and releases explosive miniatures. Trickstar and Stealth Mode take damage of Mini Shark.

A D-Shark is available from the beginning in the Deployment Center.

Archie Comics
When Sigma-1 built an army of Mavericks to defend his base on the Lost Hex in Worlds Unite, the D-Rex appeared alongside such constructs as Eregion, the D-1000, Raider Killer, and the Shadow Devil.