Quoted from Jason_Jehosaphat:No, it's "on the half shell."
Look it up.
Oysters, for instance, are served on the half shell, which means the top half of the shell is discarded and the oyster is presented on the plate in the lower half of the shell only.
Maybe you don't eat oysters.
For the TMNT song lyrics it is IN not ON...that is what he was pointing out.
https://genius.com/Teenage-mutant-ninja-turtles-teenage-mutant-ninja-turtles-theme-song-lyrics