another sacrifice question

[imFourth of Phils]

so i cast and put {Volrath's Curse} on one of opponents creatures, to cancel the effect for a turn, opponent needs to sacrifice a permanent, and {Volrath's Curse} is in his/her play, can opponent sacrifice {Volrath's Curse} or just the permanent opponent owns?

thanks

[Remillo]

The important part here is this:
Even though the Aura is attached to an opponent's permanent, you still control it.  You can't sacrifice a permanent you don't control.

[imFourth of Phils]

ooohh.. thanks