Raw peanuts which are soaked in water then fried. This process causes the the peanut to show little blisters on the exterior and produces a crispy nut. This was actually an early production method used to remove the skins from the peanuts before the frying process.
Trader Joe's (at the time of this writing) sells a good brand "Old Fashioned Blistered Peanuts" and they can be purchased salted or unsalted.