Either I saw this on another board, or there's an epidemic of hazy purple things... 

I once saw purple/violet/lavender/whatever auras around my feet while lying in the bathtub...only time I ever saw it, it was quite persistent (I also blinked, looked away, looked back, etc).

Figure I wasn't sleeping, since I didn't drown...

Anyway, my color/aura didn't move, so I'm fairly sure it was just my own personal aura.  I have, however, seen a small (size of a large pea) shiny "thing" that looked like an animated blob of mercury bop around in a way that was relevant to the situation at the time, and also persisted past blinking, changes of focus, etc.  I would think that was probably more like what you had, and I am fairly sure that was John, given what it did and where and when it did it.

People who know more will be along shortly, I'm sure.