Patron of Rot

Flash
When Patron of Rot enters the battlefield, target
creature in your graveyard gains Scavenge until
end of turn, the Scavenge cost is equal to its
mana cost.
Undying (When Patron of Rot dies, if it had
no +1/+1 counters on it, return it to the battlefield
under its owner's control with a +1/+1 counter
on it.)