Graveyard Shift

Exchange your graveyard and library. Then shuffle your library.

Whenever a player casts an instant or sorcery spell, each other player copies that spell. Each of those players may choose new targets for their copy.

If a Zombie you control would deal combat damage to a player, instead that player mills that many cards. Whenever a creature card is put into an opponent's graveyard from their library, exile that card and create a 2/2 black Zombie creature token.