Black Sun's Twilight
Up to one target creature gets -X/-X until end of turn. If X is 5 or more, return a creature card with mana value X or less from your graveyard to the battlefield tapped.
"Where once there was complacence, Sheoldred brought ambition, and soon the will of Yawgmoth reigned." —Monument inscription
Illustrated by Jonas De Ro
This printing
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You can cast Black Sun's Twilight without a target (presumably with X equal to 5 or more) just to return a creature card. However, if you do choose a target, and that target is illegal at the time the spell tries to resolve, the spell won't resolve and none of its effects will happen. You won't get to return a creature card to the battlefield.
The creature card you return, if any, isn't a target of Black Sun's Twilight. You choose it as Black Sun's Twilight resolves if X is 5 or more.
