Rakuhouha

Rakuhouha (落鳳破? lit. "Falling Phoenix Crush), is the special technique and Giga Attack that Zero learns after defeating Cyber Peacock in Mega Man X4. By pressing the S.M. button while on the ground, Zero will cry "Get ready!" before slamming his fist to the ground, causing nine bolts of destructive energy to erupt in a fanned out manner. The projectiles are not only capable of going through walls - coupled with the fact that there are nine of them, providing a decent range - but they are also capable of destroying most enemies in one hit.
Rakuhouha is the only technique of Zero's in Mega Man X4 that has its own energy meter, and because Rakuhouha is powerful and has excellent range that surpass any of Zero's moves alone, it can only be used sparingly as it uses up 12 units of Weapon Energy per use.
This Giga Attack is Storm Owl and Sigma's (2nd phase) weaknesses.