Undertale is a 2015 indie role-playing game by Toby Fox, famous for its boss battles and memorable soundtrack. The Gaster Blasters are the grinning skull cannons fired by Sans during his notoriously difficult fight at the end of the Genocide Route, with W. D. Gaster tied to their name in the game's hidden lore. Clips of the battle's sounds spread quickly on YouTube and meme pages, and the short charge-up became a favorite for edits because its dramatic buildup works like a warning cue for an unstoppable attack. It remains a staple in gaming memes and Undertale tributes.