Must be either Synchro Summoned, or Special Summoned from your Extra Deck by banishing 1 Tuner Synchro Monster and 1 "Black-Winged Dragon" from your face-up field and/or GY. During your opponent's turn (Quick Effect): You can Tribute this card with 4 or more Black Feather Counters on it; destroy all cards on the field.
eBay