(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When this Siege enters, up to two target creatures each get +2/+0 and gain vigilance and haste until end of turn.

Create two 3/2 red and white Warrior creature tokens with "Whenever this creature and at least one other creature token attack, put a +1/+1 counter on this token."