What are some things you can do with clay and only clay?

-you can make sculptures but unless you buy some findings you can create your own jewelry like studs, necklaces, bracelets, ring, ankle-let (?) , keychain, phone charm, and more! :) if you do, i recommend watching tutorials by great inspiring sculptures like gentlemanbunny, cutetanpopo, and jellyfishcharms .By clay I am going to guess you mean earth clay and what is unique about it that it is ceramic - once fired it is hard and partly glassy and will withstand many chemicals and higher tempertures than many other materials. Forms of ceramics can be used to melt metal and for bakeware for cooking as well as protecting the space shuttle.
Make a bong