Float double aerial
From SmashWiki, the Super Smash Bros. wiki
The float double aerial, abbreviated FDA, is a glitch in Super Smash Bros. Brawl that occurs when the player uses the float with a back air or neutral air, sending the player too high and far inside their opponents. This glitch can only be performed with Peach.
To perform the technique, float fairly high off the ground, perform a back air or a neutral air, and then release in direction of the opponents. If done correctly instead of dealing 12% damage, the player do 21% damage for both. This attack lounges slightly if done correctly. Because of her down aerial can combo into an up air, another back air or another neutral air naturally in the air, which allows for this combo to inflict up to a total of 37% damage. This glitch works well for edgeguarding.