We used Elmers Glue, mixed with water, a small balloon, half of a paper cup to hold the balloon, and a roll of medical gauze.
We dipped pieces of our gauze in the glue mixture and draped it over our balloon. We made sure to have it touch the table so that when it dries the ghost has something to stand up on. We let our ghost dry over the weekend. Once dry, we removed the cup and balloon and had a free standing ghost! We added eyes and smile of course!
This is the second time I have done this with students. The first time was with bigger balloons and older students. If you would like to see that, check it out here.