Sans is the short, hoodie-wearing skeleton from Toby Fox's 2015 indie RPG Undertale, beloved for lazy puns and a surprisingly dark streak. The 'sun shining, kids in hell' gag is a fan-made remix of his humour, pairing bright weather with a grim punchline, and it has circulated through Undertale meme edits and animation clips for years. Creators keep using it because the contrast is instantly funny: cheerful visuals with a morbid twist only Sans could sell.