Myfanwy
Myfanwy, whose real name is Max Klemke, was a ScienceMadness user who, at the young age of fifteen, allegedly died, presumably during his attempt at synthesizing phosgene. He was an example of how being negligent with safety in a chemistry environment can lead to serious consequences.
Background
Born 1994, Klemke joined SM in October, 2009. Klemke frequented the Energetic Materials sub forum, posting information and questions involving very dangerous and deadly chemicals, such as acetone peroxide, hydrogen cyanide, and phosgene. His posts ended suddenly after posting of phosgene.
Klemke also posted videos of his dangerous experiments on YouTube, his channel can been viewed here.
Videos and dangerous experiments
As stated before, Myfanwy had a YouTube channel with a similar name, depicting some of his often dangerous experiments without taking proper safety procedures. Most of his more dangerous videos were deleted from his channel, presumably after his death, though some of them can be found, reuploaded by other YouTubers. Such videos include: