There are several generations of Dancing Hank available. The one I am going to talk about here is the Don Wayne style Dancing Hank. Although the actual Don Wayne version is no longer available, except used, there are other versions similar enough that you can purchase today.
In the demo what I say is factual, I remember seeing the Copperfield special with the Dancing Hank, then ordering one and getting it a little while later. when I opened it I was thrilled, an ingenious gimmick and almost instantly I could make the hank dance around the black cloth. According to the instructions you start and finish by bringing the hank out of your jacket, but since I did not wear a jacket I knew there must be some other way of starting and finishing this effect, it was just too good not to use.
Couple decades later we are doing a Haunted House and we had a witch scene that we wanted to be a little different. Thus came the idea of a witches hat on a cheap plastic pumpkin. We always got good results from it (mixing magic in at a haunted house can really create some atmosphere) and best of all you could stop and start it at any time.
Couple years ago I brought the prop to a small show, pulled out the pumpkin with the witches hat, and did the effect similar to what is on the demo, again it went over well and it was practical, at least for me. While it does not have the awe of the full routine, not even close, at least I was getting some return on my investment so many years before. It could also be used as a running gag during a show.
Any witches hat will do, you may have to stuff the top part to make it stand up. The pumpkin is simply one of the plastic trick or treat carriers you see small toddlers carrying around on Halloween. Cut a hole about the size of a half dollar just above the base and slide the gimmick in and you are all set. These pumpkins can be purchased for about a buck during the Halloween season, but after Halloween you can really stock up on them as they will go for as little as a quarter each.
This effect with the hat and pumpkin probably isn't for everybody, but for me it solved certain problems I had starting and finishing the Dancing Hank.
Couple comments the Dancing Hank in general. Angles can be "Zombie Like" and the Dancing Hank cannot be performed surrounded. The angles on the pumpkin effect are even worse since you do not have the cover of the black cloth. The effect is moderately priced at $40 and .less. Setup time is almost non existant (this depends on how you start the effect)
Clearly show both sides of a cloth, nothing AT ALL to be seen. Suddenly an 18" silk appears dancing about behind the cloth! The Silk jumps towards the audience, up your arm, even peaks up and down! NO Rubber Gimmick to Break at the time of performance!