(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, target player sacrifices a creature or planeswalker of their choice and loses 1 life.

Menace

At the beginning of your end step, put a +1/+1 counter on this creature if a permanent was put into a graveyard from the battlefield this turn.