This is what it looks like when the Feds want to know what you've been up to.

According to a Gizmodo article, a mechanic found this device tucked neatly behind a vehicle's exhaust pipe during a routine scheduled maintenance service for a client's car.

Initially the mechanic thought it was a pipe bomb, but eventually correctly determine the device to be a Guardian ST820 manufactured by Cobham. Even more alarming for the vehicle's owner - the tracking device in question is used exclusively by the army and law enforcement.

So, if you see one of these taped to your car one day, you can officially panic.