And now you can buy one.
USBKill USB Kill devices for pentesting & law-enforcement
Don't Plug It In! How to Prevent a USB Attack
The USB Killer, Version 2.0
This USB 'killer' will destroy pretty much every device in its path
USB Kill Stick
Infected USB Devices: How to Prevent USB-Based Attacks
The USB Killer, Version 2.0
USBKill USB Kill devices for pentesting & law-enforcement
Infected USB Devices: How to Prevent USB-Based Attacks
The USB Killer Stick Will Destroy Your Computer, be Careful!
USB Killer, yours for $50, lets you easily fry almost every device