Portent of Vengeance

Portent of Vengeance's power is equal to the
greatest power among attacking creatures.
At the beginning of combat on your turn, untap
all creatures you control. Until end of turn, they
gain haste and trample and can't be blocked by creatures with power 2 or less.
At the beginning of each end step, return Portent
of Vengeance to its owner's hand if it dealt
damage this turn.