Electronic demon costume is surprisingly unnerving
hackaday.com
hackaday.com
for anybody interested: 8:30 demon costume
I guess it would be tricky to fit an optical sensor under that under the mask, but maybe you can track eyeball motion by tracking the muscle movement around the eye?
Some quick tests (i.e. placing my hand on my face and moving my eyes around wildly) suggests that it might be doable. :) Possibly just by tracking how your nose twitches...
But eyes that are randomly wandering around are actually kinda creepy, too... :-)
But in all seriousness, I'll bet it would make a lot less difference in the dark.
With that in mind, it's almost 4.2% more unnerving than the alternatives.