Shuttle Loop
Shuttle Loop is the name of Meta Knight's Up B attack. Seen in this screenshot and in a few videos posted outside the Dojo, Meta Knight jumps into the air with his sword pointed upwards, goes into a loop and glides forward with his blade extended. The Shuttle Loop does around 9% of damage, and has good knockback.
It should also be noted that the end of the shuttle loop attack automatically initiates a glide, which can be used in addition to the vertical recovery to add good horizontal recovery. In addition, because Meta Knight can do a quick attack to conclude a glide, the shuttle loop can be timed to do two consecutive attacks--the initial upswing, and the quick swing to conclude the glide.
One should be careful when using Shuttle Loop while facing off of the edge, for unless you quickly cancel the glide, you could easily glide right off the stage with no chance of recovery.
The Shuttle Loop is actually a pre-existing maneuver. It was first used by Kirby in the SNES game Kirby Super Star when he received the Wing ability.
