SansGen

SansGen is the slash ship between Sans and Arataka Reigen from the Undertale and Mob Psycho 100 fandoms.

Canon
As both characters are from different series, they have never interacted. Sans is from a PC game, while Reigen is originally from a web manga series. They are both major characters in the their respective series, Sans being a supporting character or final boss in the Undertale series, while Reigen is the mentor and boss of the main character of Mob Psycho 100.

Fanon
Both are extremely popular characters in their fandoms, if not the most popular. They both have lots of fanart, and people will "thirst" over both characters. Because of their fame as characters and their simps, they have both gained status as "Tumblr Sexymen".

The ship started when Twitter account Tumblr Sexyman OTD hosted a poll where people could vote on who the Ultimate Tumblr Sexyman is, after Reigen had won multiple other polls he did not qualify or qualified for with weird reasons. Sans and Reigen were the finalists on the poll. Because the poll became extremely popular on Twitter, many people made fanart of the poll, mostly tagging it under both #SANSSWEEP and #REIGENSWEEP, which progressed from them fighting, to ship art.

On September 8th, 2022, Queen Elizabeth II passed away. Because of the large impact the meme was having on Twitter, fans jokingly said that the poll is what killed the Queen. Queen Elizabeth makes an appearance in some Sansgen art because of this. Many people will portray the paring alongside Sansmaeda, another infamous Sans crackship. Either with Nagito and Reigen competing for Sans' affections, or all three of them in a polyamorous relationship. Some art also features Reigen and Sans together with Hatsune Miku after Reigen lost to her in another poll.

Fandom
FAN FICTION

TUMBLR

TWITTER

Trivia

 * In the tumblr sexyman poll by sexymanOTD, Sans and Reigen were tied almost the entire round. However, Sans ended up winning the poll by 0.1%. The poll had 244,809 voters, and ended on September 7th, 2022.