Rule 359.3.e.5

If any of the spell's targets are no longer legal, those game objects, players, or zones are unaffected by the spell as it resolves. Any instructions related to an illegal target can’t be followed. Example: A player plays Void Seeker, a spell that says "Deal 4 to a unit at a battlefield. Draw 1." The unit's controller uses a Reaction to move the unit to their base. Since the unit is no longer a legal target, it is not dealt any damage. Void Seeker's controller still draws 1. Example: A player plays Bellow’s Breath targeting a unit in combat that reads in part “I can’t be chosen by enemy spells and abilities unless I’m in combat.” In reaction, that unit’s controller plays Flash, moving the unit to their base. The unit is no longer in combat, so it is no longer a legal target for Bellow’s Breath. The unit will be unaffected by Bellow’s Breath as it resolves. Example: A player plays Hidden Blade from the facedown zone at a battlefield, targeting an enemy unit. In reaction to Hidden Blade, their opponent plays Tideturner from facedown at another battlefield, choosing to swap locations with the unit Hidden Blade targeted. When Hidden Blade resolves, the chosen unit is no longer at the appropriate battlefield, so any instructions related to that unit are ignored.