Unsustainable Necromancing

Join Forces (Whenever a black creature you control dies, each player starting with you may pay any amount of mana. Each player, starting with you, may then return a card with converted mana cost less than or equal to the amount of mana paid to their hand. Then every player, starting with the player to your left loses life equal to the amount of mana paid.)
In desperate times like these, there is no knowing what you will end up doing.