Introduction: Halloween Hand Grab Scare / Floating Head Illusion
This is a really great prop scare for Halloween trick or treaters: A creepy table that grabs their hand when they try to take the treats.
The table can be used for many other illusions which you can experiment with at Halloween.
This instructable is an improvement on a number of 'floating head' illusion tables I have seen in the past.
Have a look at the movie. A more detailed description of the construction follows.
Step 1: Background
These disembodied head illusion tables are relatively common. You might have seen them in museums or theme parks where visitors can try them out and take photos.
Three versions are shown above. The problem with these is that there is either a mirror directly facing the audience, or a pair of mirrors facing outwards at 90°. This means that the reflections in the mirror must be very carefully controlled. In the first example the audience cannot get too close or their line of sight too low, and in the second and third examples, there needs to be a specially constructed surround for the illusion which doesn't look very natural.
Step 2: An Improved Illusion
Then I remembered that I had seen a version of this effect in an old magic book: Magic Simplified by Harry Baron (1954). The description is of an illusion where a magician carries a fake head to a table; when he puts it down, it appears to move and talk by itself.
But - the crucial thing is that the mirrors face inwards at 90° rather than out to the surrounding area. This means that you don't need to install a special surround for the effect to work and the audience can get fairly close without discovering the trick.
Of course the compromise is that the table then appears to have five legs (one in each corner and one in the middle). It makes the table look a little strange, but this is what we are after anyway. It did not seem to matter at all in practice.
The first thing I did after re-discovering this illusion was to make a little model (shown here) to find out if the effect was going to work and if it was worth proceeding with a larger model. It did and so I did.
Step 3: Planning and Cutting Material
Above is a sketch of the table showing the main parts.
This is the basic cutting list.
5 x softwood legs 680mm long, 3 of these cut with rebates as shown to accept the mirrored panels.
15mm plywood tabletop 800mm dia, with offset hole 210mm cut out.
2 x mirrored panels 350mm x 680mm
note on materials:
I was using whatever I had to hand. Plywood is good for the top because it is strong and flat.
The mirrored panels are sheets of 6mm MDF covered with very thin 1mm styrene mirror sheet. This is quite unpleasant stuff but it is cheap. It is brittle and snaps easily while also being very soft so it scratches easily. It does not give a perfect reflection either, but in the low light used for this illusion it is sufficient. Better materials for the mirrored surface would be acrylic or glass mirror.
note on cutting:
I cut the two circles in the plywood using a router attached to a rod which was fixed to the middle of the sheet. It worked very well. The rebates in the softwood were also cut using a router. Everything else cut by hand.
Step 4: Assemble
Use these hex drive threaded inserts to attach the legs to the table top. They are not the most robust solution, but quick to use and easy to dismantle. I used M10, but slightly larger or smaller would be fine. Drill a small countersink in the table top so that the bolts don't stick up.
Paint everything matt black.
Step 5: Basket and Grabbing Hand
For the hand grabbing scare, you need to place your treats in a bowl or basket.
I found a woven basket on a market stall, which I sprayed black.
Before cutting the hole in the bottom, I used hot glue around where I wanted to cut to stop the weave unravelling.
Otherwise you could use a plastic bowl and (carefully) cut a hole with a dremel or saw.
Any black glove will work for the grabbing hand. Use hot glue to cover the top of the glove in candies.
Step 6: Final Effect
I found some cheap velvet online which we used for the table cloth and to cover a circular piece of cardboard for the base.
Placing (battery powered) tea lights in the front gives a good effect as these are reflected in the mirrors and further lights can be placed behind the mirrors in case anyone looks round.
The effect is best placed in a narrowish hallway so that visitors are not tempted to walk around it.
Looking carefully at the base it is possible to see the edges of the mirror, but in low light this is not very clear and no one seemed to notice it.
The 'Hand Grabbing' person needs to sit behind the mirrors with their gloved hand inside the basket, surrounded by candy.
It is best to have someone next to the table to invite kids to take the candy.
After several experiments, we found it best to let the kids take one or two candies first, then the person next to the table gives a verbal cue (e.g. "Happy Halloween") so that the person behind the mirror knows when to grab.
The table looks good with some candles, too, but watch out - the scare can really make people jump!!
This was very popular last Halloween. After the trick or treating was over, the kids took it in turns to take pictures with the floating head illusion.
Of course there are many other possibilities for this prop such as pulling things out of a hat (or something placed on the table), making something on the table move etc.
Have fun with your own project and Happy Halloween!