Aether

Aether is a special skill that can be used by Ike from the Fire Emblem series in Super Smash Bros. Brawl. In Super Smash Bros. Brawl, he throws his sword into the air, leaps up to catch it, and comes back down while slicing the air, instantly knocking out someone with a single stroke. He is resistant to attacks as he performs this move; he will still take damage, but he wouldn't even flinch. However, in the game Fire Emblem: Path of Radiance, it does not instantly knockout someone but instead gives an opponent heavy damage and recovers health equal to half of that damage.