Don't ever let this guy walk around when someone is in a sensory deprivation tank.
Tangentially, are those still used? There was a fad for them (especially combined with LSD) something like 40 years ago, but I've hardly heard of them since.
Sensory deprivation tanks (aka float tanks) are still a thing. Here's a business in Atlanta with float tanks. (I've never tried a float tank, so I can't speak to their efficacy.)
This seems significant:
http://www.theguardian.com/science/2015/aug/18/first-almost-fully-formed-human-brain-grown-in-lab-researchers-claim