Onslaught

You may assign this creature's combat damage divided as you choose among defending player and/or any number of creatures they control.

Until end of turn, whenever a player gains life, that player loses 2 life for each 1 life they gained.

At the beginning of each player's upkeep, that player gains control of this enchantment. When you gain control of this enchantment from another player, choose a creature you control and an opponent. Flip a coin. If you lose the flip, that opponent gains control of that creature.