The thought of eating live worms that would eat you from the inside out if you didn't chew them up thoroughly has always grossed out the strongest of men but I have eaten many things during my travels that would compare like earthworm burgers, raw horsemeat sushi and rice with bee larva all of which actually tasted good but the worst thing I ever ate was called natto which is fermented soy beans with the consistency of lumpy rubber cement that smells like dirty gym socks that have been in the trunk of your car during the hottest days of the summer. The trick is to not breath while you eat it.
What is the grossest thing you have eaten? (Be graphic)
Liver, that literally tasted like what crap smells like...
I wouldn't want to eat gagh. I'll keep my intestines the way they are.
I told my Japanese students that I would eat anything but liver and they put me to the test with the above items. My mother tried hiding liver in other foods but I could always smell it before I ate it.
EDIT: I just noticed you said "be graphic." Copied from another thread that touched on the craziness of Icelandics, here is an approximate history of how Hakarl came to be:
"Well, we catch these huge sharks, and they have a lot of meat on them. Problem is, anyone who eats it dies horribly."
"Hmm. Seems like a real shame to let all that good fish meat go to waste."
"Well what if we buried it in a gravel pit for a few months and let it rot? Maybe it will be more edible then."
"Worth a shot."
"Did it work?"
"No, Skjeld just tried some and he's vomiting blood."
"Okay, let it dry out for a few months and try again."
"Well, the good news is we can eat it and live. The bad news is it tastes like limburger cheese that's been soaked in ammonia, and the smell for the curing shed is so horrible it makes the surrounding countryside uninhabitable."