Contest of Dragons

Target two dragons in play. Each dragon's owner reveals two random cards from their deck for
each dragon targeted and adds their combined
mana cost to that dragon's power. If one of the
two dragons has a total power lower than that of
the other dragon, bury it. If one of the dragons
was buried in this way put a +3/-1 counter and a menace counter on the dragon that was not
buried. Shuffle the revealed cards back into their
owner's libraries.