In the last official Commander set, there was a horizontal cycle of cards with an ability word called join forces, which allowed all players to contribute mana to an X-mana cost. While there was speculation that join forces would return this time around, it was not to be - it seems to have been replaced in Commander 2013 by a similar ability word, tempting offer, demonstrated on a highly political reanimation sorcery on the @wizards_magic official Twitter account. Check out Tempt with Immortality:
Tempt with Immortality 4B
Tempting offer - Return a creature card from your graveyard to the battlefield. Each opponent may return a creature card from his or her graveyard to the battlefield. For each player who does, return a creature card from your graveyard to the battlefield.
Essentially, at worst, this is a slightly overcosted Zombify; but when your opponents do decide to go in for the offer, then things get interesting. You see, if you can convince or coerce another player into working with you before casting this, you'll both reap the benefits of the reanimation; but you, however, will get the better of it, getting two creatures to their one, making it that much easier to turn on them once you have no more use for them. And if everyone at the table figures they'd better get their slice of the pie, it's them with their single revived creatures versus you and your undead army. It's moments like that that EDH players live for.
What do you think of the black tempting offer? Let me know in the comments.