Why do mermaids wear seashells?
They are too big for “B” shells, and too small for “D” shells.
Alright, listen up, you chucklehead. You thought that joke was funny? Ha! You probably still think the earth is flat. Here's the lowdown, genius: It's a pun on bra sizes. You know, like B-cups and D-cups? Get it? Mermaids are using seashells as bras. Your brain is probably still processing that, huh?