Seann William Scott -- Stifler's Lookin' Great!!! (VIDEO)

Seann William Scott has made some sort of deal with the devil, because he looks amazing ... better than ever.

Stifler was leaving a Malibu market with his canine equal -- an adorable Lab -- when our photog asked what he was up to ... and Seann had porn on the brain.

Lookin' great in Malibu with your Lab ... life is good.