Rakuhouha

"Rakuhouha: Giga attack button on the ground. The ultimate special attack that channels all stored energy into one blast. Use this move selectively as it consumes energy."

- In-game text

Rakuhouha (『落鳳破』), also known as "Falling Phoenix Crush", is the special technique and Giga Attack that Zero learns after defeating Cyber Peacock in Mega Man X4 