A variety of lobster with a flat tail, shaped somewhat like a slipper, which is the edible part. The Mediterranean slipper lobster is generally used for flavouring soups as it does not carry much meat. However, the Australian variety from Queensland, Scyllarides squammosis, is a good meaty lobster. It is found in warm waters.
Flat-shelled oysters include such varieties as Les Claire, Belons, Gravettes and Marennes.
The husks of the seeds of Plantago ovata, psyllium. They are used as an ingredient of natural laxatives. In India they are used in the long, cool drinks available in India. They absorb the flavours of the drink and take on a jelly-like consistency.
I asked 'Serious Eats' for a description of a Flint-style Coney and was told that it is made with a Koegel's natural casing hot dog, imported from their Flint factory, served on a steamed bun with Coney sauce, onions and mustard only. What makes Flint-style unique is the dry, loose meat Coney sauce ... NOT a red sauce or chili sauce and NO beans or sauerkraut. There is a picture on the link, with thanks to LunaPier, and thanks too to FastFoodCritic.