The Simpsons fans spot X-rated mistake hidden in latest Halloween special

The Simpsons accidentally gives fans an eyeful

The episode, Treehouse of Horror XXXVII, aired on October 25 and followed Bart and Lisa as they visited the Department of Motor Vehicles (DMV) while searching for Homer. 

During one establishing shot, viewers could spot a website address on a sign outside the building, intended as another joke about the inefficiencies of the DMV and the US government.

Unfortunately, the domain had not been registered, giving one prankster an opportunity to take the joke somewhere the show's writers probably hadn't anticipated.

After buying the address, the individual reportedly created a website featuring an animated topless image of Marge Simpson's sisters, Patty and Selma. 

Not exactly the sort of family entertainment you'd expect to stumble across while watching a cartoon.

Clicking on the image apparently made the experience even stranger. Visitors were reportedly met with a remix of “Who Let The Barts Out?” followed by a montage of additional pornographic Simpsons material. So much for a quick exit.