MTG >Combos >Altar of the Brood +Phyrexian Altar +Unearth +Eternal Witness +

Cast Unearth targeting Eternal Witness When Eternal Witness comes into play, return Unearth to your hand Altar of the Brood will trigger, the opponent mills a card Sacrifice Eternal Witness with Phyrexian Altar to add one black mana Repeat the process.