SuperWhoLock refers to the massive crossover subculture and fan community that emerged on Tumblr in the early 2010s, merging the fandoms of Supernatural, Doctor Who, and Sherlock. The term represents a megafandom where fans would create art, fanfiction, and memes depicting the Winchesters, the Doctor, and Sherlock Holmes interacting in a shared universe. While it began as a way to celebrate three of the most popular shows of the era, it eventually became a self-aware meme within internet culture, often used to describe the peak of the Tumblr era obsession or the chaotic energy of multi-fandom crossovers. Today, it stands as a nostalgic monument to a specific era of internet fandom history.