Each creature you control gains
vigilance (Attacking doesn't cause this creature to tap.),
trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.), and
melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked with a creature this combat.) until end of turn.
At the beginning of the next main phase this turn, draw a card for each player who was dealt combat damage this turn.