Chit'lins, headcheese, haggis and whatever that nastiness is that echooos said.
Avocados. I can't stand them in any way, shape or form.
Pickled beets. During holidays I am the one in charge of spooning them out of the jar and placing them on a serving dish thing. The juice stains everything severely, and the smell is horrid! It seems nobody in my family shares my distaste for them, though. Yuck!
Rockmelon/canteloupe, I'm not sure what everyone else calls them, but even looking at them makes me gag
Jellies eels was the first thing that came to mind, for all I know, they may well be delicious, but I just cannot get past the look of them.
I enjoy most foods but I'd drawn the line at Hakari: An Icelandic dish of rotten, buried, fermented shark.
When I was a kid my parents made three things that totally grossed me out:
Duck Blood Soup
Prune Soup with Beef Neckbones
My mother always said "I cooked it, you're going to eat it or get a beating!" I just took the beating, I figured I would get one if I ate it and hurled anyway, so cut to the chase, beat me and get it over with!
Coleslaw. Creamy kind is tolerable but the kind made with oil is just ....ugh for me.
Live octopus. Aren't they worried it will wrap a tentacle around their uvula on the way down?