Text (LE): 5/3. ; ~this~ can't block. ; Whenever ~this~ deals combat damage, sacrifice a permanent.
If this card leaves play before it deals combat damage, then you do not have to sacrifice a permanent. If it leaves play because of combat damage or after combat damage, you do. [Legions FAQ 2003/01/23]
You only sacrifice one permanent, no matter how many things it deals damage to. [Legions FAQ 2003/01/23]