Grapple Beam
The Grapple Beam is the name of Samus' extended Grab in all three installments of Smash. It is a blue, energy beam that grabs onto opponents and brings them to Samus, but when it misses, Samus is vulnerable. It is learned in almost every Metroid game. In games which it is not in, it is replaced with the Power Grip, in which when Samus is near a ledge, she will automatically grab it. These two techniques (the ledge grab and Tether Recovery) are also in the Super Smash Bros. series (the Tether Recovery being Brawl-exclusive), seemingly coming from this series.
In Super Smash Bros
In Super Smash Bros., the Grapple Beam was Samus's grab, but could not be used in mid-air.
In Super Smash Bros. Melee, the Grapple Beam, when used in mid-air, not only damaged opponents, but could also perform a wall-grapple. In certain versions of Melee, it was possible to double the length of Samus' Grapple Beam by mashing the D-Pad while using it. Once this is done, one must press the A button as the tip touches someone in order to grab them.
In Super Smash Bros. Brawl, the Grapple Beam could be used to perform the Tether Recovery and also could be used to damage opponents in mid-air. The Grapple Beam also had a cameo role in the Subspace Emissary, as Samus used it to try and pull a R.O.B from a Subspace Bomb.
The lag from missing with the Grapple Beam can be reduced significantly if one uses it while dashing.