With the Arrow-verse and John Constantine on The CW, it would be very easy to pull the Winchester brothers in for a superhero adventure.
Maybe that adventure is better off as a Blu-ray release for Scooby-Doo fans.
Or, Supernatural could just do a “Scoobynatural Part 2,” and throw in Scrappy-Doo and the Harlem Globetrotters?
It’s hard to imagine The CW worries too much about what gets tried on Supernatural now that it’s 13 seasons in, but if there were any reigns, they’ve surely been loosened with the success of this crossover.