Extras roll a single die as described above. But Wild Cards roll an extra d6 and take the highest of their normal die or the “Wild Die” when making skill or attribute rolls. Wild Dice are rolled just like the Trait die, and can Ace as well (see above).

Critical Failure: The downside is that snake-eyes (double 1s) on one of these rolls is a critical failure. The GM gets to make up something rotten to happen to your character. That's the price Fate charges for making someone a hero.

Example: Buck Savage, international adventurer, faces wild-eyed cultists. He has a d10 Shooting and rolls his d6 Wild Die. The Wild Die comes up 4, but he Aces (a 10) on the d10. He sets the Wild Die aside and rolls the d10 again. He gets another 10, then rolls again and gets a 3. His total is (10+10+3) = 23!

Savage Worlds Deluxe Edition p. 71