Kitten loves to play with this stuff! It is probably no news to a lot of you but I have never seen it and was as amazed as Kitten. Basically you mix 2 parts of cornstarch with 1 part of water. The resulting mixture looks like liquid but feels like solid. I also like to let Kitten play with the starch before I add water. To play I assemble spoons and cups, sometimes I add a little food coloring and just let her explore.
Last time I added a sheet of blue paper and encouraged her to dribble the mixture on it, it is quite interesting, unfrtunately when it dries it crumbles off paper, so no keepsake value here.