Bill Cipher is the triangular dream demon and main antagonist of Gravity Falls, the Disney animated series created by Alex Hirsch that ran from 2012 to 2016. Fans lifted his playful, menacing voice lines into edits, memes and soundboards, where this peekaboo clip became a favourite for surprise reveals and mock-scary moments. Its popularity grew through short-form video and fan animation, helped by how instantly recognisable Bill's voice and design are. Years after the show ended, creators still use it because a single innocent word from such a sinister character creates an immediate, funny contrast.