Text (US+errata): Prevent all damage that would be dealt to you by sources you don't control. ; When a card is put into your graveyard from anywhere, sacrifice ~this~. [Oracle 2008/10/01]
Buyback (see Rule 702.24) causes a spell to go to your hand instead of your graveyard, so using Buyback will avoid triggering this card to be sacrificed. [D'Angelo 1998/10/08]
Discarding does trigger this. [DeLaney 1998/10/17]
