The '4chan Party Van' is a legendary internet slang term and meme used to suggest that the FBI or other law enforcement agencies are monitoring a user's activity and are en route to their location for an arrest. Emerging from early imageboard culture in the mid-2000s, the 'Party Van' became a shorthand for federal surveillance following high-profile raids on hackers. The meme typically features a nondescript surveillance van and is used ironically to mock people who post illegal content or try too hard to be edgy online. It has since become a cornerstone of internet 'raid' culture and a classic way to tell someone that they've finally crossed the line.