Nemesis of Mortals | Magic: The Gathering
Formats Nemesis of Mortals is Legal in
Official Oracle Text for Nemesis of Mortals
: Monstrosity 5. This ability costs less to activate for each creature card in your graveyard. (If this creature isn't monstrous, put five +1/+1 counters on it and it becomes monstrous.)
Official Rulings for Nemesis of Mortals
9/15/2013 : Once you declare you’re casting Nemesis of Mortals or activating its ability, it’s too late for players to try to change the number of creature cards in your graveyard to affect the cost of doing so.
9/15/2013 : Once a creature becomes monstrous, it can’t become monstrous again. If the creature is already monstrous when the monstrosity ability resolves, nothing happens.
9/15/2013 : Monstrous isn’t an ability that a creature has. It’s just something true about that creature. If the creature stops being a creature or loses its abilities, it will continue to be monstrous.
9/15/2013 : An ability that triggers when a creature becomes monstrous won’t trigger if that creature isn’t on the battlefield when its monstrosity ability resolves.