This unusual loop relies entirely on the interlocking paradox created by Jon Irenicus, Shattered One and Seasinger. When Jon Irenicus bestows his dark blessing upon Seasinger at your end step and hands it to an opponent who controls no Islands, Seasinger's state-based ability immediately tries to force its sacrifice. However, the un-sacrificable clause granted by Jon Irenicus strictly forbids it from leaving the battlefield this way, causing the game to relentlessly trigger the sacrifice check over and over again in an unbreakable mandatory loop. Because this interaction cannot be stopped or declined, the game is forced to a draw.