Cannot be Normal Summoned/Set. Must be Special Summoned by its own effect. If a card(s) on the field is destroyed by a card effect: You can banish 1 LIGHT and 1 DARK monster from your GY, except "Chaos Nephthys"; Special Summon this card from the GY (if it was there when the card was destroyed) or hand (even if not). You can only use this effect of "Chaos Nephthys" once per turn. If this card is Special Summoned: You can target 1 card your opponent controls and 2 cards in their GY; banish them.
