These slippers have an air balloon in the heel.  When the child steps on it, the air shoots to the front lifting the eyes or mouth. I bought the unicorn for my daughter and the dragon for my son.  There is a huge difference between the quality/engineering of the two models.  The unicorn has light weight eyes so they lift up easily. She loves hers.  However we've ordered two sets of the dragon slippers and they only last about two hours.  The difference is that the blast of air in the dragon has to lift it's mouth and eyes so there are two tubes coming from that balloon.  If one tube fails the entire slipper doesn't work.  I used a seam ripper to open up the dragon, hoping I could fix it.  The pieces were held in place by cheap tape.  The tape had collected fuzz and lost its stickiness.  I was able to fix it, but it was not worth my time.  If you order Stompeez be sure to order the ones that only lift up they eyes, otherwise they are not worth your time or money.