Hero's Last Stand

If you control only one creature, Hero's Last Stand costs {r}{w} less to cast.
Target creature you control gains undying until
end of turn. (When it 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.)
Until end of turn, whenever a creature enters the battlefield with a +1/+1 counter on it under your control, it fights a creature you don't control.