Eruption (噴火 Funka) is Ike's standard Special Attack in Super Smash Bros. Brawl. Ike lifts his sword then plunges it in front of him which then explodes in a burst of flames. It can be charged up to 5 seconds, and the fire greatly increases its range. When fully charged, it deals enough damage and knockback to be a One-Hit-KO on on most characters near the edges of Final Destination, and causes 10% recoil damage to himself, similar to Roy's Flare Blade. The knockback caused by this move is mostly vertical when it isn't charged alot and becomes more horizontal when it is. Graphically, it resembles the animation of the Bolganone spell in Fire Emblem: Path of Radiance. Like most of Ike's moves, it is powerful enough that charging is not required for it to be effective. The flames reach high up, so there is a large vertical hitbox as well. There are also smaller hitboxes below, far in front of, and behind Ike. Interestingly, the move has the most knockback (though not damage) when released just before being fully charged (while Ike is flashing red). This is known as a Flash Eruption.
This attack, like Ike's Aether, possesses Super Armor. The moment that the Special Button is released to the point where the Ragnell hits the ground are launch resistant frames. As Ike is particularly susceptible to juggling due to his high weight and falling speed, the super armor frames can be useful for defending against it. A fully charged Eruption can break any character's shield, provided that it was not a Perfect Shield. It can also be a meteor smash when sweetspotted on the tip at the very end of the hitbox. It's quite a weak spike, and it's impracticality makes it rarely used on purpose (if at all) in competitive play.