A wavedash is a technique in Super Smash Bros. Melee that is performed by air dodging diagonally into the ground, causing the character to slide a short distance.
(Jump)->immediate (Diagonal Air Dodge)
Continuous Wavedashes with Marth.
Sheik punishes Falco's shield pressure with a wavedash out of shield followed by a dash attack
Captain Falcon does a frame-perfect ledgedash (wavedash from the ledge) and pivot edgehogs