Brand: UntuckIt (Rumuage)
In There’s Something About Mary (12x21), Dean wears this shirt from when they capture Toni until the end of the episode.
In Who We Are (12x22), Dean continues to wear this shirt for the entire episode.
In Scoobynatural (13x16), Dean is wearing this shirt when he shows Sam where he put the TV in the bunker. He then get sucked into Scoobydoo and this shirt gets cartoonified. He wears it for the rest of the episode (except a brief scene when he is in a cartoon nightgown in the mansion.)