Sheik dashes forward and slashes with her knife. If she catches anyone, the Sheikah eye symbol will appear onscreen, and she will proceed to slice in many directions, before finally launching the trapped opponents.
Origin
While this move does not pull from any Zelda game, the Sheikah eye represents the Sheikah clan, of which Sheik is a part of.
Notably, Sheik has carried a dagger on her person in previous Smash games, but has never used it in her moveset; ironically, such dagger is absent outside of this Final Smash in Ultimate.
