Sans comes from Undertale, the 2015 role playing game by Toby Fox, where he became one of the most recognisable characters thanks to his jokes, glowing eye, and difficult boss fight. Doge comes from the long running meme built around a Shiba Inu photo and broken English captions that spread widely in the early 2010s. Putting the two together follows a familiar internet pattern of remixing serious game icons into absurd meme versions, and the clip keeps circulating in gaming edits because both references are instantly understood by players.