Shuttle Loop
Shuttle Loop is the name of Meta Knight's Up special move. 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, making it one of Meta Knight's few finishing moves.
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. The glide from this attack is slower than his regular glide, and allows better control.
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. Also, landing while in the glide puts you on the floor, and the opponent can easily punish you. Using the Glide Attack right before hitting the floor completely cancels the attack AND landing lag, leaving you completely ready to use any move or evade an incoming attack that would have otherwise hit you.
Trivia
- It's actually possible to control the Shuttle Loop's glide in a way that will allow you to travel all the way around the bottom of some stages and grab the ledge on the other side. This most notably happens on Final Destination and the Temple.
- The Shuttle Loop is what people calls the loop-de-loops in the Sonic Games, the most famous of which is the Green Hill Zone Act 1 Shuttle Loop.
Origin
A move very similar to and using the name of Shuttle Loop was used by Kirby in the SNES game Kirby Super Star when he received the Wing ability. The only differences here are the gliding and Meta Knight's sword, in addition to the fact the Wing ability's attack required you to toss an enemy first.
The way the glide is controlled is similar to when Mario flies through the air using a Cape Feather in Super Mario World.