Earwax flavored jelly beans.
I played the jelly belly game with my kids (Beanboozled I think?) and ate a vomit flavored jelly bean. It was as awful as you can imagine. I had to quit or the next bad one would have had me racing to the bathroom. Our youngest was five at the time and had continually picked the good flavor of whatever color she landed on. When she finally picked wrong she fearlessly chomped on a sour milk jelly bean-poor thing almost threw up all over the table.
Whoever came up with that game was an evil genius.