In the third episode of “Supernatural” Season 3, an installment entitled “Bad Day at Black Rock,” a phone call alerts the Winchester brothers that someone has broken into one of the father’s old storage facilities, where they discover a cursed lucky rabbit’s foot that gives bad luck when someone else comes into possession of it. The episode also introduces secondary adversary Bela Talbot (Lauren Cohan), a ruthless thief who steals supernatural objects and sells them to the highest bidder. Bela, it turns out, is after the cursed bunny appendage in order to make some cash, but the brothers come out on top and the object is destroyed — but not before she gets away with Dean’s winning scratch-off tickets. At this point, Ackles went off script, shouting one of Dean’s signature lines “Son of a b****!” The unexpected exclamation causes Padalecki to grin and he’s barely able to keep himself from laughing.
Padalecki discussed the blooper that made it into the show at a fan event and how he was able to keep himself from ruining the shot. During the Salute to “Supernatural” convention in Los Angeles in March 2008, a fan asked the actor about the suppressed laugh at the end of the episode. He explained that it was at the end of a long steadycam shot that had multiple techs holding lighting instruments and boom mics, calling it a “big orchestra of 50 people doing this at the same time.” Basically, he said, the shot had to work out perfectly and then his onscreen partner went off book. “It wasn’t scripted,” he said (via YouTube). “We were just supposed to watch her drive by and look at each other, and I’m kinda like, ‘You got what you deserved.’ And he goes ‘Son of a b****!’ And I was like ‘If I ruin this, they’re gonna string me up.”