The worst thing I ever choked down was poached eggs. It was at a friends grandmothers and would have been very impolite not to have eaten them.
I don't care for much of anything pickled.
Their has been many things I refused to stick in my mouth either because of looks or smell, but that wouldn't count.
The worst thing I ever swallowed (probably at least 10 times) before it ever got in position to be spit back out was a raw oyster.
Through the southeast for some reason everybody is crazy over boiled peanuts, another spitout food.
I heard about balut years ago, all I can soy is they must have had some very good stuff to drink over there to even get a guy to think about putting that stuff in your mouth.