A simple USB stick, created by a Russian security researcher known as Dark Purple, can instantly fry any device it's plugged into, including your laptop or TV. "These devices perform only one function - the destruction of host machines."In a short video posted by Dark Purple, the USB stick is shown in action - it kills the test machine within seconds of being slotted in.After the laptop has been turned off the demonstrator in the video tries repeatedly to turn it back on but it seems that the USB stick has blown its circuitry.The stick destroys computers by sending a 220V charge through the interface to blast the circuitry.Dark Purple claims in a Russian-language blog post that the rogue stick can be used to incapacitate almost anything equipped with a USB port. The examples he gives are smartphones, TVs, routers and modems.His goal, he writes, is to test prototypes of "devices that perform only one function - the destruction of computers."After the USB stick is done with a computer the motherboard will have to be replaced.But "it is extremely unlikely that the hard disk or the information on it was damaged," Dark Purple wrote.This is good news because it means that hackers who get their hands on a poisoned USB won't be able to wipe the data stored on your computer's hard drive, which is probably more valuable to you or your business than the computer itself.Security researcher Graham Cluley warned: "Yet another reason not to plug a USB stick of unknown origin into one of your computers." ..