On September 7th, 2015, season 2 episode 15 of Gravity Falls aired on Disney XD. In one scene, Stanford shows Mabel and Dipper a scroll with a symbol resembling Bill Cipher on it. He asks, “Do either of you recognize this symbol?” Dipper answers, “Bill.” Stanford says, “You know him?” and Dipper says, “Know him? He’s been terrorizing us all summer!”
The earliest known meme using screenshots of the scene was posted by Twitter user @GravityWiki on September 21st, 2015. The meme replaces the word “symbol” with “man” and the image on the scroll with Alex Hirsch, Grunkle Stan’s voice actor (shown below). The post gained over 520 likes in seven years.