We stumbled across the above video on Twitter (courtesy of Mr Tom Whitwell) and, although it's not actually representative of the way guitar strings move, we think you'll agree that it does look cool as cucumbers.
According to a group of scientifically minded Reddit.com users, the effect is created due to the rolling shutter of the mobile phone camera.
The camera doesn't capture every region of the frame at once, so when the strings are filmed vibrating it captures some parts of the image at the top of the string's 'swing' and some at the bottom of it.
The end result is a composite image of a 'wobbly' string that's coincidentally similar to the sound waves actually created by the string (or at least a graphical representation of them).
We'd like to underline the fact that this is not how a guitar's strings actually move, though. This video of guitar strings in slow motion reduces the speed by 2,000 and 4,000 per cent so you can see the true effect of the vibrations created when you play.