Corn is the cob vegetable often cooked in the same seasoned pot during a Cajun seafood boil. Boil cooks commonly add corn on the cob alongside crawfish, shrimp, crab, sausage, and potatoes so the vegetables absorb the spicy, salty cooking liquid while the seafood cooks.
Corn fits the dish’s regional history as well as its practical cooking style. Native American foodways helped make corn an important ingredient in Louisiana, and Cajun cooking favors locally available foods prepared in large pots. Cutting ears into short sections makes them easy to serve and helps them cook evenly with the other ingredients.
The contents of a seafood boil vary by family, restaurant, season, and locality. Potatoes, onions, garlic, and smoked sausage are frequent additions, while mushrooms or other vegetables may appear in modern versions. That flexibility does not make the answer ambiguous: among the listed cob vegetables, corn is the standard and recognizable choice.
A seafood boil is also not the same as every traditional Cajun dish. It is a communal preparation associated with Louisiana and the Gulf Coast, and many contemporary boils use commercial spice blends or regional variations.