Kaiō-ken

Kaiō-ken (界王拳, Fist of the World King) is Goku's down special move in Super Smash Flash 2. Goku powers up for about 5 seconds before transforming into Kaiō-ken Mode, making him stronger, faster and more deadly. But this transformation has it's costs, as Goku starts taking 10% of damage per second (so by 10 seconds of playing as him you'll have +100%). He gains a new side special move and a second teleportation on top of his up special move. His standard special move is toned down a bit but he becomes faster in everything else.