Corn Succotash

I have gone around the entire day saying 'Corn Succotash' to myself. Not loudly I think, but still. The problem is that I can not deduce where it comes from. It is a fun thing to say so I do not suffer indefinitely but as I neither knows what it is nor why it is on my brain it kind of annoys me. (If I would have to guess I would say it is something that someone says in M*A*S*H but I have not watched an episode of that show in years...)