Argentum Masticore (Phyrexia: All Will Be One)

Artifact Creature Ñ Phyrexian Masticore - First strike, protection from multicolored
At the beginning of your upkeep, sacrifice this creature unless you discard a card. When you discard a card this way, destroy target nonland permanent an opponent controls with mana value less than or equal to the mana value of the discarded card.