Removing a big toe and using it to replace a lost thumb.
Making short people taller. They break their legs over and over. Ugh!
I have a friend who had a small palate. They cut the roof of his mouth and inserted a device. He would use a key every night and turn the device two clicks to widen it. It was very painful. Once it was the right width he then had to have braces to straighten his very crowded teeth.
A friend had to have a needle injection into his pupil.
~ made my toes cringe ~
I would have to say, that some of the Sex change operations from Man to Woman, sound crazy and super painful . . .
I don;t know abpout "craziest", but the fecal implant is higg on the "yuuck" faxctor