The Recto Rotor. Words fail. I’m not sure shoving a light bulb where the sun don’t shine is a great deal of improvement. “Honest, Doc, I saw it on the Internet!”
“If it’s on the internet, it must be true!”
Radium: As late as the 1980s, some guy was leading tours of people into an old radium mine to breath the air for 10 minutes or so. OTOH, a president of Westinghouse, iirc, had consumed so much radium water, his jaw "rotted" off. That's not to mention Madame Currie.
Crosley XerVac: There was the FlowBee twenty years ago.
Chest Hair toupee: Well, there were merkins too, but the current trend's been denudation.
Spray on hair: Even Ron Popeil couldn't fool all the people even part of the time with that one.
The prostate warmer seems just as bad to me.