Bill Cipher is the triangular dream demon and main antagonist of Disney's Gravity Falls, which ran from 2012 to 2016 and was voiced by series creator Alex Hirsch. His well well well greeting became one of his most quoted lines because it captures his mix of playful charm and real threat. Clips of the moment spread on YouTube, TikTok and soundboards as a shorthand for a villain showing up, and it remains popular in fan edits, reaction videos and memes about unexpected arrivals and schemes being revealed.