W. D. Gaster is a hidden, lore-heavy character in Undertale, the 2015 role-playing game by Toby Fox, who is linked to fallen experiments, Wingdings text and Entry Number 17. He never appears in a normal playthrough, which helped fans turn his distorted sounds and fragmented files into a symbol for secrets and alternate timelines. Clips of Gaster glitching spread through YouTube theories, fan games and meme edits, and remain popular because the noise instantly signals a corrupted character or a truth the game was not meant to reveal.