Tech blogs went crazy over the weekend after a new self-driving car was seen rolling around Arlington, Virginia.

Unlike vehicles from Google Waymo, Uber and others, the car didn’t have any obvious signs of a Lidar array, the chunky imaging technology most autonomous vehicles use to gauge the state of the road ahead. Instead, it had just a small bar mounted on the dashboard, which blinked red when it was at a stop light and green once the cost was clear.

Even more intriguingly, the car appeared to be genuinely autonomous: there was no-one sitting in the driver’s seat. Typically, a human overseer is required in the testing phase to make sure that the car doesn’t go wild and run over a marching band, but somehow this car had managed to find a loophole.

The timing made sense: just a week beforehand, Virginia had authorised the testing of self-driving cars in the state, albeit initially only on closed lanes of two highways, but eventually expanding to “light traffic conditions”. And local university Virginia Tech has been testing autonomous cars – and autonomous drones – in the area.

But still a question remained. Who was behind this breakthrough new technology? How were they solving the problems that had stymied even the mighty Alphabet/Google/Waymo megacorp?

You’ve read the headline. You know the answer: it was a bloke dressed up as a car seat.

Adam Tuss of NBC Washington tracked the car down, tailing it around the city until he could pull up next to it at a red light to get some shots of the interior. What he found wasn’t exactly what he expected:

Adam Tuss (@AdamTuss) This is one of the strangest things I've ever seen @nbcwashington @ARLnowDOTcom pic.twitter.com/8ipKEnkeiq

The car was being driven by a man disguised as a car seat, holding the steering wheel low and leaning far back into his own seat. When Tuss tried to ask him questions – “Brother, who are you? What are you doing? I’m with the news, dude” – he reportedly skipped the red light and sped off.

But one aspect of the rumour mill was correct: the guy really was associated with Virginia Tech. According to the university’s transportation institute, he was engaged in research about autonomous vehicles, likely gathering data about the reaction of normal drivers to sharing road space with a self-driving car.

“The driver’s seating area is configured to make the driver less visible within the vehicle, while still allowing him or her the ability to safely monitor and respond to surroundings,” a VT spokesperson said.