Karen, Destroyer of all

Haste, vigilance, trample, annihilator 5, infect
When Karen, Destroyer of all enters the
battlefield or attacks, target opponent mills 20
cards and discards 3 cards from their hand at
random.
When a permanent is sacrificed, milled, or discarded, put it onto the battlefield under your control. If it's a creature, it gets -3/-3 for the
next 5 turns.