The Mystic Tan is a strange apparatus that applies self-tanning solution. It's really a sign of the times. The machine is marketed primarily to people who worry about damage from UV rays, but still feel compelled to cultivate a Paris Hilton-esque orange glow. It is meant as an antidote to the difficulty of applying traditional bottled self-tanning products, which often results in streaks or incongruous white patches where the person applying it couldn't reach.
The Mystic Tan solution is a combination of self-tanning chemicals and bronzer. The former are readily available in any drug store and act by mystically inciting skin cells to up their pigmentation. The latter provides a "healthy glow" while the tanning solution takes effect (it takes a few hours) and is for all intents and purposes a full-body coating of brown paint. There are several settings for the level of bronzer, ranging from English Starlet to Offspring of Victoria Gotti.
If you're going near a Mystic Tan, make sure you're waking up alone or with someone who really loves you the next morning, as the bronzer will collect in the creases of your skin overnight, making you look quite freakish.
The machine is a big blue booth, like a shower. The solution shoots from several nozzles, the machine beeps (meaning the person inside should turn around), and then it sprays again. Before stepping inside the machine, the manufacturers recommend applying a "barrier cream" to hands and scalp, paper slippers to the feet, and eyewear to protect the eyes. They also provide a nose plug, for those who can't hold their breath while the machine is spraying and risk having their nostrils and lungs self-tanned.
This is not what I've been up to. I just happen to know some people who own a tanning salon.