Burn Runner

Whenever this creature enters or attacks, exile the top card of your library. Until the end of your next turn, you may play that card. If tht card was an instant, sorcery, or enchantment spell, this creature deals 3 damage to any target. Strike {5}{r}(You may cast this spell for it’s strike cost reduce by the amount of noncombat damage you dealt to opponents this turn. If you did, put a finality counter on it and it gains haste until end of turn. Sacrifice it at the end of combat. Timing restrictions still apply.)