Boost grab
Boost grabbing is a technique in which the momentum from a character's dash attack is transferred into a dash grab. The result is a longer ranged dash grab, which is most noticeable with Sheik (whose dash grab range is nearly tripled) and Fox, while in Brawl, it is notable with Snake which he is required to use to regrab certain characters when they roll away from his dthrow and also required to regrab characters like Falco out of grab release. Discovered in Super Smash Bros. Melee, the boost grab is a very quick and useful form of dash attack canceling. By completely canceling the dash attack, the user suffers far less lag. This move is more useful than a dash attack if the player wants to prevent themself from getting hit. Although this attack looks useless, leading the player to think that they can just press Z to save time, the Boost Grab is a very good Mindgame.
The grab can be replaced with an up-smash to perform a dash attack canceled up smash (DACUS).
Performing a boost grab
To perform the boost grab, the player must first dash. Then, press the attack button while dashing to perform a dash attack, then press the grab button immediately within the first frame to grab. If done correctly, the dash attack will be canceled and the player will skip straight to a grab. If they skip the first frame of the dash attack and then grab, then the player won't do a boost grab and will suffer, due to the lag of the Dash Attack.
A good method of practicing this is to go into Training Mode and choose Mario. Attempt to boost grab, and if Mario's dash attack sound is accompanied by a grab, the boost grab was successful. This can be practiced with Wolf in Brawl because his boost grab retains his dash attack sound, and Meta Knight also retains his dash attack sound.
In Melee
The boost grab is easier to perform in Melee. However, the player can't jump cancel the boost grab and only Sheik, Fox, and Falco benefit from it.