In a nutshell: If you see a shady character playing with a Game Boy near your car, beware: they might be a thief. Rather than being one of the beloved retro consoles, the device is used to trick a car into thinking it's a key fob, allowing the user to unlock and start the vehicle.

Keyless entry and ignition systems may be convenient, but they offer criminals a high-tech way of stealing cars. One popular method is the relay box technique, which involves holding one box to the wall of a house so it can pick up the signal from an owner's key fob. This is transmitted to a second box that is held close to the vehicle. Once a car detects the signal from the second box, its sensors are tricked into believing the key fob is present.

With one of these devices, which look a lot like a Game Boy, there's no need to relay a signal from a nearby fob. As per the Daily Mail, they record the car's data and act as a responder that the vehicle recognizes as an authorized proximity remote. The car will then open and start as if the user had a valid key fob.

A Bulgarian firm called SOS Auto Keys sells the gadgets under the promise of being the "most advanced locksmith tool." The company does warn that the device should not be used by anyone with "unlawful intentions," which should definitely dissuade hardened criminals.

One piece of good news for those worried about their vehicles is that the gadgets are costly: £20,000 (around $25,000).

"As fast as car technology evolves, criminals are working just as hard to cheat these systems. What is most worrying is that something sold decades ago has been repurposed to help thieves. With plenty of old gadgets collecting dust, some will tinker with them in the hope they can unlock a car," said Jack Cousens, of UK motoring association AA.

"Thieves have leveled up from playing Grand Theft Auto on a console to using the console to commit Grand Theft Auto."

Image credits: Daily Mail and tuaindeed