Shark Boomerang

Shark Boomerang is a special weapon that Mega Man obtains by defeating Shark Man in Mega Man 3 for the PC. It fires a three-bladed boomerang, presumably sharpened around the edges, straight forward.

It looks very similar to the Gyro Attack and acts like Rolling Cutter in that it returns to Mega Man.

The Shark Boomerange does 8 damage to Wave Man, 6 damage to Blade Man and Torch Man, 3 damage to Oil Man, as well as 4 damage to Wily's Second Form.

Trivia

 * In the games data, there are unused sprites of "weapons unlocked", where Mega Man is holding his new weapon.