Phantasm Spiral Grip

Equip only to a Normal Monster. It gains 500 ATK. When the equipped monster destroys an opponent's monster by battle: You can Special Summon 1 "Phantasm Spiral Dragon" from your hand, Deck, or Graveyard, and equip it with this card, then inflict 500 damage to your opponent. You can only use this effect of "Phantasm Spiral Grip" once per turn.