So, not exactly a pillow but if you haven’t already seen this then go take a look at the £100 ‘Mermaid pillow’ – a sequinned cushion which changes colour when you brush it. I’m not sure it would be very comfortable to sleep on but it sure is mesmerising.
Note – October 2017:  Not the real thing but a much cheaper alternative is now available via Amazon.  Although they’re calling it a pillow, it’s clearly just a cushion cover. But with 21 different shimmering choices and for £6, I’m definitely putting one each in the stocking for my teenagers at Christmas time. Available here.