Boomer, Serpent Slayer

+1: Target creature gets -2/-2 until Boomer, Serpent Slayer dies or is put into exile. That creature remains tapped for your next two turns.
-3: Create a 6/6 blue serpent token with haste, trample, and reach that has "when this creature dies, destroy target creature".
-11: Deal damage to each opponent and each creature on the battlefield equal to the number of creatures in up to two graveyards.