"Seafood" joke

Joe and Obie, on a trip to see the ocean, decided to try some of that seafood they had heard so much about back home. At the Captain's Retreat Restaurant, Joe ordered baked flounder and steamed lobster legs and Obie asked for a huge plate of oysters. "What's this OH NATCHREL mean?" he asked the waiter.

"That means we cook the oysters and bring them to you just as they came from the sea," the waiter responded.

Thirty minutes later, Obie began experiencing horrendous stomach cramps so Joe called a taxi and rushed him to the emergency room of a large hospital.

When the examining doctor learned Obie had eaten a plate of oysters less than an hour before, he asked, "Were those oysters fresh?"

"I don't know doc," Obie groaned. "Until today I have never seen an oyster, let alone eat one."

"Well, what color were they when you shelled them?" the doctor asked.

Joe and Obie looked puzzled.

"SHELLED?" they asked.