Eraphon, God of Monsters

Cast this spell only if your devotion to black, red,
or green is three or greater.
Creatures you control with mana value four or
greater have monstrosity 2. Their monstrosity
cost is equal to their mana cost plus {2}.
Whenever a monstrous creature you control
attacks, double the number of +1/+1 counters on
it. It gains trample until end of turn.