Ordeal of Erebos 99 (Theros)

Enchant creature Whenever enchanted creature attacks, put a +1/+1 counter on it. Then if it has three or more +1/+1 counters on it, sacrifice this Aura. When you sacrifice this Aura, target player discards two cards.

NM - $0.70
LP - $0.70
MP - $0.70
HP - $0.70
DMG - $0.70