Vanish
Vanish is Sheik's Up B move. It involves her throwing a Deku Nut and vanishing into thin air. Using the Control Stick, players can determine where Sheik will reappear by tilting in a certain direction. Vanish does not go as far as Farore's Wind, but transforming in midair is not recommended, as the transformation takes time, and barely slows her descent. The initial explosion deals damage and knockback, and is capable of KOing at around 120%, but has a noticeable start up lag.
The re-entry of Sheik's Vanish has a very small Push effect. This can be seen as it moves an opponente further than simply landing on them would. It has just enough push to knock someone, standing near the edge, off it, causing them to cliffhang.
Origin
Sheik often vanished in The Legend of Zelda: Ocarina of Time, much to Link's bafflement. However, sometimes fire or sand concealed her disappearance while she quickly threw the Deku Nut on the ground. Impa, the only other Sheikah in the game, could perform this ability; it is one of the "Sheikah arts".