Mal'Dreir Barer of Pestilence

Mal'Dreir Barer of Pestilence attacks every turn if able.
{1}{b}{r}, attackig creatures with power less than Mal'Dreir Barer of Pestilence gain +3/+3 until end of turn.
Creature you or your opponents control with power greater than Mal'Dreir Barer of Pestilence can not attack.