Shadow Mega Man, known as Shadow Rockman (シャドーロックマン Shadō Rokkuman) in Japan, is an enemy that appears in Plug Man's stage from Mega Man 9. He runs faster than Mega Man and tries to run him over to cause damage, but jumps lower than he does and can't shoot. He appears behind Mega Man if he walks in front of certain panels on the wall, and is likely a simple hologram created by these panels scanning Mega Man. He isn't easy to kill, but can be often tricked into running off a ledge or into spikes (a weakness which they amusingly share with the real Mega Man).
Shadow Proto Man
Shadow Proto Man, known as Shadow Blues (シャドーブルース Shadō Burūsu) in Japan, is the enemy that appears in place of Shadow Mega Man when playing as Proto Man. He acts precisely the same way as Shadow Mega Man.