[mothered]

I partly agree with you, but I believe it is possible, maybe software does prevent changing anything, but if someone can create an USB (not the current one, I think it's to small), which has enough capacitors you should be able to let it crash. I do not think it can set on fire, only way to do that is overloading your GPU or CPU I think.
So maybe it is possible.

I certainly agree that It Is possible.

Irrespective of the USB's (In this case) ability to cause hardware damage, my Implementations preclude the device from being Identified by the system on which It's plugged Into. I'm not saying It's the case with all devices of this nature with greater capability, obviously I haven't tested everything that's out there.