These three peppers all came from the very same plant. I've never seen a bell-shape on Giant Marconi's before. All others on the plant were normal long ones. The bell shape was growing around the wire of the cage, which accounts for the bent shape, but you can still see the fat bell shoulders on the bottom.
I got the seeds from TGS, and I know Giant Marconi is a hybrid, but how common is it to have both forms on one plant?