Styropyro plays with fire on his YouTube channel, and the latest video shows him playing with a ridiculously dangerous laser, intended for tattoo removal, that he bought on eBay.
I was searching for a Nd:YAG laser cavity for a future project when I came across a bunch of tattoo removal devices on eBay. They claimed to contain a Nd:YAG laser but at a small fraction of the cost of buying the parts separately. Skeptical, I bought one anyway since I had the option to return it if it didn't live up to the seller's claims.
Much to my surprise my unit turned out to be INSANELY powerful.