Sidisi, Emerging Plague

Deathtouch
Whenever you copy a spell, mill two cards. If a
creature card is milled this way, create a 2/2
black Zombie creature token.
Whenever Sidisi, Emerging Plague attacks, you
may sacrifice another creature. When you do,
search your library for a card with mana value
equal to the sacrificed creature's power, reveal it,
put it into your hand, then shuffle.