Hadoken

The Hadouken (波動拳) is a move from Capcom's Street Fighter series that was included in as a secret power-up obtained from a Light Capsule in Mega Man X, Maverick Hunter X, Mega Man Xtreme and Mega Man Xtreme 2, and is executed in the same way, inputting the combination ↓↘→+ATTACK while X's health gauge is full and he is on the ground to unleash a powerful energy ball. It can kill most bosses and enemies in a single hit.

In Mega Man X4 Hadouken is one of Magma Dragoon's attacks. In Mega Man X: Command Mission the boss Ninetails uses the Annihilator Hadoken (滅殺波動拳 Messatsu Hadouken). In Project X Zone X uses a powerful Hadouken alongside Zero's Genmurei.