Selene Vess, Necromancer

+1: Each player discards a card, gains 1 life, and creates a 2/2 black zombie creature token with, "This creature can't be sacrificed."
-2: Each opponent sacrifices a creature for each token they control.
-6: Create 10 2/2 black zombie creature tokens with deathtouch, then target player sacrifices 20 permanents.