If this card battles a monster, neither can be destroyed by that battle. If this card is Normal or Special Summoned: You can send 1 Fiend, Illusion, or Spellcaster monster from your Deck to the GY, then you can make this card's Type become the original Type of that sent monster. If this card is in your GY: You can banish 1 Spell from your GY; Special Summon this card. You can only use this effect of "Fleeting Phantom Mask Master" once per Duel, and its previous effect only once per turn.