In Melee characters with a tether grab like, Samus, Link and Young Link can extend their grab using this technique. To perform a Decagrab you must cancel the landing lag of a zair and dash attack using and holding a grab input (Z, R + A, L + A), keep holding the grab input after the dash attack, this will cause the dash attack to cancel into an extended grab after the tether despawns.
References
https://docs.google.com/document/d/1N0XBRQz8DmCkTIRAh8nJa2tcjP2PhMG0riRnj1e4nho/edit?usp=sharing