Metal Blade

Metal Blade is Metal Man's weapon in Mega Man 2. It shoots a small gear that can be shot in eight directions. Metal Man fires his straight and as jump-shots; he's never on the ground and attacking at the same time. It instantly kills Metal Man himself. Even though it is the weakness of Flash Man, Bubble Man, and Wily Machine 2, but it does decent damage against Wood Man, and Picopico-kun.

Trivia

 * In Mega Man 3, there is a weapon called Shadow Blade that is similar; except it shoots in six directions instead of eight.