Cast this spell only during combat on an opponent's turn.
Return X target creature cards from your graveyard to the battlefield. Sacrifice those creatures at the beginning of the next end step.
11/7/2014 The delayed triggered ability that makes you sacrifice the creatures will trigger only once. If you don’t sacrifice one or more of those creatures at that time (perhaps because another player gained control of them), the ability won’t try to make you sacrifice them on future turns.