It isn't the first time that Dean's crossed paths with a powerful witch. They're nasty things; he's always hated witches, ever since he was old enough to recognize them and learn what they are. Spiteful and mean and full of venom, they have always been on Dean's shit list, if only because they use far too many bodily fluids for his tastes. A lot were petty, too - dealing in hex bags and leaving them for people to die in horrible ways, or stealing years of their life via a damn poker game.

Nah, he's not a fan.

When he and Sam discover there's some suspicious goings on somewhere up in Maine, they're not in much of a position to actually go together, and sometimes that happens - they'll take separate jobs so more gets done, especially if it's something one of them can handle on their own. Dean isn't really happy about a witch hunt on his own, but he doesn't realize that's what it is until he's face to face with the guy, but luckily for Dean, the bullet hits home.

They're only human, after all. Old and full of magic, but human for the most part.

He drops like a sack of potatoes and it's Dean left with a smoking gun and frazzled nerves, looking around the junked up room in distaste.