A tether grab (also referred to as a Z-Air or an aerial grab) is an aerial attack that can be performed in Super Smash Flash 2. The attack is performed by pressing the grab button while in the air. When the button is inputted, the character will throw out its tether, which will latch onto any close ledge (called a tether recovery, seen below) and damage any opponent on contact. It is used mainly to recover, but it can be used to attack as well.
A tether recovery is a type of recovery move in Super Smash Flash 2 that allows the player to latch onto the ledge of a platform with their tether grab or special move. It is performed by using said tether grab or special move in midair near a ledge, causing the object to grab the ledge and making the character automatically snap to it. The tether recovery will fail if the ledge is currently occupied when used, though the attack may also knock the character off of the ledge before grabbing it, allowing the tether recovery to succeed.