The line comes from the American version of The Office, in the 2008 episode Frame Toby, when Michael Scott, played by Steve Carell, discovers Toby Flenderson has returned to Dunder Mifflin. His horrified outburst became one of the show's most quoted moments and spread widely as a GIF and sound clip on social media. The joke works because Michael treats a coworker he dislikes as a personal disaster. Years later it remains a go to reaction for dread and disbelief online.