If I have a unique card in play with a text that says something like "Sacrifice this card to do (X)" and have already played a duplicate for it, what do I do?
The "Sacrifice" rules say that a sacrificed card cannot be saved, the "Duplicate" rules say that the duplicate's interrupt effect cannot be cancelled. So what happens if I sacrifice this card to do (X)? Do I indeed sacrifice it to do (X) and place both the card and its duplicate on my discard pile, or can I discard the duplicate to do (X)?