Ouroboros

Flash
Chose a color, Ouroboros is the chosen color.
Join forces, Cummulative Upkeep {4}: Starting with
you, each player may pay any amount of mana
to pay for Ouroboros's Cummulative Upkeep cost.
Players can't win or lose the game.
Pay 3 mana of the chosen color: Sacrifice
Ouroboros, use this ability only as a sorcery.
{5}: Destroy Ouroboros, any player can activate
this ability.