Extreme Speed
ExtremeSpeed is Lucario's Up-B move. Lucario stops moving for a brief moment and then dashes in a chosen direction. While doing so, it may turn slightly (you can actually control the angle of the curve some-what by tilting the direction via control stick). Additionally, it can wall cling while dashing, aiding its recovery.
In the Pokémon games, ExtremeSpeed is a move that always goes first, similarly to Quick Attack, but more powerful. Unfortunately, in SSBB, Lucario's ExtremeSpeed does no damage. Also, there is noticeable lag at the end of the move. Nevertheless, its still a decent special recovery move. Strangely enough, in the games, ExtremeSpeed is one of the more damaging Normal-type moves, with a base power of 80.
The Subspace Emissary boss Rayquaza also uses Extremespeed as an attack. Rayquaza zooms across the screen and then returns to it's idle position. Unlike Lucario's ExtremeSpeed, this attack does damage.