I used to be a nurse, and I remember an older colleague telling me about the woman who had a cystoscopy (endoscopic examination of the bladder) due to repeated bladder infections - and they were somewhat surprised to find a goldfish skeleton in there!
We also had a chap who had heard you could get sexual pleasure from a cylinder vacuum cleaner, but didn't realise that you did this by using the hose end, so put his penis in the end with the intake fan - which promptly sliced his penis like a cucumber. After reconstruction, he was left with a very short stump.