Equip only to a Level 5 or higher Fiend or Zombie monster. When an attack is declared involving the equipped monster and an opponent's monster: You can make that opponent's monster lose ATK equal to the equipped monster's ATK. You can activate 1 of these effects;
• Fusion Summon 1 Fusion Monster from your Extra Deck, using monsters from your hand or field.
• Special Summon 1 "Doppelganger Token" (Level 5/ATK ?/DEF 0) with the equipped monster's Type, Attribute, and ATK.
You can only use this effect of "Spirit Illusion" once per turn.