While I was at a group dinner at a Chinese restaurant, a whole fish was brought to our table. One of the other people at the table told a story of another time a whole fish was brought to the table.
He attended the wedding rehearsal dinner of a family member. The bride is Chinese, but the groom is not. (Or maybe it was the other way around. Doesn't matter to the story.) The dinner was banquet-style at a Chinese restaurant, and one of the many courses was a whole fish.
Two of the non-Chinese attendees marveled at the presence of an entire fish right there in front of them, head, tail, fins, and all. I guess they had up until then only been served fish that had already been filleted, or at least had the head cut off. One of them nudged my acquaintance and said, "We'll give you $500 if you eat the eyeball."
These guys inadvertently created their own sucker bet.
For you see, eating the eyeball is common in many parts of Asia. In fact, whenever their family has fish, my nieces fight over who gets the honor of eating the eyeballs!
I don't know whether my acquaintance cheerfully accepted the bet or whether he explained that their bet was a poor choice to offer a Chinese person.
What food-related sucker bets exist in your culture? (I'm not talking about foods like chicken feet or tongue, which are clearly prepared and served to be eaten. I'm talking about things that an uninitiated person might consider to be a garnish or an inedible by-product, like shrimp heads.)
Update: I remind you that the question is not asking for foods which are served as dishes on their own.