Nova Strike

Nova Strike (ノヴァ・ストライク) is the Giga Attack of the Ultimate Armor and the Force Armor. X first surrounds his body with immense energy, then performs an invincible flying tackle that plows through (and destroys) enemies almost effortlessly.

In Mega Man X4-X6, X can use this attack infinitely (except in the Force Armor's version, where energy needs to be refilled like normal Giga Attacks). In Mega Man X8, the Nova Strike is modified along with the Ultimate Armor. It now has Weapon Energy (WE); however, it recharges over a small period of time (a matter of seconds, in fact). The only downside to this is that it prevents the Nova Strike from being used over and over. To compensate for this added weakness, the Nova Strike's travelling distance is increased, and it can now destroy all bosses in only two hits (the first hit depletes nearly 75% of a boss' energy, triggering the boss' overdrive, which is always mandatory).

In Mega Man X: Command Mission, X's Ultimate Armor is much different from the previous versions, and his Nova Strike is a series of explosions and powerful amounts of damage done to the enemy. It is one of the two strongest Hyper Modes of the game, along with Zero's exclusive Absolute Zero.

Other appearances
In the Mega Man Zero series, Copy X's first form uses an air dash attack that slightly resembles the Nova Strike.