Time Stone

When Time Stone enters the battlefield target
player plays their next turn backwards
(Untap, combat, main phase, draw, pass)
{t}{g}, Pay 4 life, Current turn starts over, all
spells played (including lands) are returned to
their owners hands, any effects that happened
are reverted, then the turn ends. the player
whose turn it was draws a card. Each player
may only activate this ability once per game.