Demon of the Final Breath

When you cast Demon of the Final Breath, you may pay an additional {c}{c}. If you do, Demon of the Final Breath gets +1/+1 and flying.
{b}{c}: Destroy target creature with power 3 or less. You gain life equal to it's toughness.
{5}{b}{b},{t}: Put three -1/-1 counters on all other creatures. If a creature would die this turn, exile it instead.