Viper

Flying, Energy 5
{t}, Remove 3 energy counters : Remove target creature from combat. You may have up to 3 creatures you control deal damage equal to their
power to that creature.
{t}, Remove 3 energy counters : Up to 2 target creatures without flying cannot block until end
of turn.
Sacrifice a building you control : Put up to 5
energy counters on Viper.