Marth Tech: Ledge Dash
Description / How To Perform
As soon as possible after grabbing the ledge to gain brief invulnerability, release from the ledge and quickly jump, then perform a 
Waveland onto the stage. The more perfectly everything is timed the more invulnerability you will have when Wavelanding on stage.
Difficulty: 
(Advanced)
Usefulness: (Generally Useful)
Extra Info
With a well timed ledge dash, each of the following options can be performed while still invulnerable: Spot Dodge, Roll, Jab, Dolphin Slash, and Grab. Note however that doing an invincible Ledgedash grab is infeasible for a human, and is TAS only. The example seen here showing Marth's model in blue when invincible is as close as I've gotten personally - 2 frames of vulnerability before the Grab hitbox is active.