Leaf Shield

Leaf Shield (リーフシールド) is Wood Man's power. It can be obtained after defeating Wood Man in Mega Man 2, Mega Man II, Mega Man: The Power Battle and Super Adventure Rockman, and is one of the abilities that Mega Man can use in the Marvel vs. Capcom games. When used, the shield will stay on Mega Man as long as he stays still, but the instant he moves, the shield will fly off in the direction he moved in.

Robot Masters And Boss Weak Against Leaf Shield

 * Air Man: Mega Man 2 and Mega Man II
 * Buster Rod. G 2: Mega Man: The Wily Wars
 * Cut Man: Mega Man: The Power Battle

Robot Masters And Bosses Immune To Leaf Shield

 * Alien: Mega Man 2
 * Hyper Storm. H: Mega Man: The Wily Wars
 * Magmard Serpent: Mega Man: The Wily Wars
 * Wily Machine 1 and 2: Mega Man: The Wily Wars

Usefulness
However, he can use the shield to ride the platforms in Crash Man's stage and the four section in Wily's Castle... plus, when the Pipis are around, he can use the shield to gain a lot of powerups.