The tension is still palpable between the Winchesters, but they decide to work another case together - a locked room murder of a young girl. Her phone reveals that the last selfies she took showed a creepy figure behind her.
The brothers soon bump into two of the Ghostfacers - the online 'ghost hunters' who've stepped on their toes a number of times before - who are also looking into the creature believed to be responsible for the girl's death.
With the rest of their group abandoning ghost hunting for "normal lives", Ed Zeddmore (A.J. Buckley) and Harry Spangler (Travis Wester) are the last of the team still chasing after spook tales.
However, much to Dean's disbelief, the Ghostfacers seem to now more about the creature they are all hunting than the Winchesters. It's the Internet-created urban myth of the Thinman - and Ed and Harry have even published a book on the phenomenon (The Skinny On The Thinman).
One of the things that first fascinated me about Supernatural was the way the Winchester family delved into urban mythology, so it's great to see this coming to the fore again - especially when it's such a recently born folktale, a definite product of the Internet age (being based on the 'real' myth of the Slender Man).
But #thinman is an episode replete with firsts beyond the fact that the Winchesters appear to be behind the curve on this particular creature.
Matters get complicated when Ed reveals a key secret behind the Thinman myth to the Winchesters and the Ghostfacers' situation comes to mirror the issues the brothers are having.
However, having become an Internet meme, the Thinman has taken on a life of its own, with final twists that echo both a famous horror film franchise and a certain well-known cartoon.
Peppered with the show's trademark humour and totally detached from the angelic civil war overarching plot of the season, #thinman was not only an impressive throwback to the show's early days but also a reminder that even after all these years hunting ghosts and ghoulies there are still things out there that can surprise our heroes.