Mecha-Arm

Mecha-Arm (メカアーム) is, as its name implies, a mechanical arm that is found in Mega Man X2. It first appears in the opening stage, and they tend to grab X and drop him either back a bit, or into a damaging area. X needs to keep moving to avoid getting grabbed. It also shows up in the level where Mega Man X defeats Violen.

Arm
Arm (アーム) is a variety of the Mecha-Arm that appears in the opening stage from Mega Man Xtreme 2. Unlike the Mecha-Arm, it attacks by shooting at the player and can be destroyed.