I suspect we've all known a Mrs Cropley.
My father's cousin in London once presented us with a 'roasted' Chicken that had seen limited warmth for about 10 minutes and still had a bag of giblets inside, my own Swedish Mother-in-Law was renowned for her Spaghetti with Hazel Nuts, and I have been seriously poisoned by 'chefs' on several occasions; most notably by a Pea, Ham, and Salmonella soup.
Luckily I have never been sick from eating dodgy shellfish, as I know that it can severely restrict one's love of such delights for ever after; and that would have been a disaster. However, I was once quite ill after a very expensive meal at a multi-starred restaurant. The meal itself was wonderful, but I think it had all been far too rich for my obviously 'selective' stomach.
I can't think of any really bizarre recipes of my own invention, other than an inspired Asparagus Omelette. I put a few spears of cooked Asparagus into the whizzing machine with two eggs. whizzed them, and fried the resulting green mush in butter. What I had imagined would be a delicious Asparagus Omelette was totally disgusting.
I would be very interested to hear of any equally nasty disasters; we could even assemble a book. The world is ready for your confessions!