If a face-up card you control leaves the field by your card effect, or to activate the effect of your card, and the card that left the field was "Stardust Dragon" or a Synchro Monster that listed "Stardust Dragon" in its text: You can apply 1 of the following effects, but you cannot apply that same effect of "Majestic Mirage" again this turn.
• Special Summon 1 of those monsters.
• Banish 1 monster from your opponent's field or GY.
• Any damage you take this turn is halved.