There was a post recently about a computer that could fit inside of a usb port, little arm chip. It was meant as an open yubikey substitute, but you could easily hide one of those inside of a mass-produced cell phone charger, and suddenly you have something doing arbitrary computation. It didn't have a wireless chip, but on the other hand it was $30, if you made it using off-the-shelf consumer parts. I'm sure an industrial complex would be able to shave the size down and potentially add a wireless chip. Scary stuff.