"Who lives in a pineapple under the sea."

Pineapple and hambeast

"A pineapple is neither a pine nor an apple, but a fruit consisting of many berries that have grown together. This also means that Pineapples are not a single fruit, but a group of berries that have fused together. The technical term for this is a “multiple fruit” or a “collective fruit”--- apropos 🤷

There must be a soft sponge inside that pineapple

A bikini bottom.