Those oysters on the 1/2 shell are alive when you eat them.
Good ol' boy was at a fancy restraunt and ordered the oysters on half shell. After they were delivered, the waiter noticed the good ol' boy was just sitting there, looking at his plate. The waiter stepped up and asked if everything was alright with his meal.
GOB: "I just cain't figger out how to eat these things."
Waiter: "Let me show you, sir." Waiter squirts a little lemon juice on an oyster, noting that it does, indeed, twitch. He then lifts the oyster with the little fork and pops it into his mouth, swallowing it whole.
The GOB watches him intently for a moment. "Dang. I did that same one three times and it jus' kept crawling back out!"