When Castiel needs help, the Winchester brothers listen.
On Supernatural Season 10 Episode 20, a heavenly assassin is taking lives and somehow leads Sam and Dean to the ultimate monster.
You may think you've seen it all before, but nothing can prepare you for what you're about to see here, because the ultimate monster is none other than a...teenage girl?!?!
And this teenage monster has a smart mouth. Thank GOD. The look on Dean's face when she calls him old is matched only by the words that pour out of his mouth like melted butter, "How dare you?!"
After all the darkness on Supernatural recently, and the frequent Rowena appearances, it's about time for a standalone hour when the guys can cut loose and have some fun, even if it means getting ripped on for being the old (yet very, very hot) creatures they've become over ten seasons.
We're ready! Bring it on teenage monster.
If you want to revisit more light installments, you can watch Supernatural online via TV Fanatic.
Carissa Pavlica is the managing editor and a staff writer for TV Fanatic. Follow her on Twitter.