One of the first effects I had as a kid was a light that came on over a selected card, I got it at the annual flower show in Detroit when I was about 10 and kept that trick for about 30 years till I finally dropped it and the plastic cracked on it. When I shopped around for a replacement, I found Ultra Spook Light, which is almost identical to the one I had bought over a quarter of a century ago so this effect is not new, but it seems to go in and out of style every decade or so.
If you have a seance act this works great, use the flashlight as a regular flashlight and no one will be the wiser. Let the audience handle the flashlight for other effects so that they know its just a regular flashlight (and it will operate as one). When you want to reveal a selection this is a fun way to do it, but there are limitations.
The flashlight is not remote control, so without going into the secret of it there is a gimmicky thingy that triggers the light that you will have to hide either below or around whatever it is they selected. What I am trying to say is that the magician really does all the work, but the light takes the credit. The light is simply a spooky way to reveal a selection, with this effect you still need to do the heavy lifting so to speak.
This effect came with a gimmicky thingy but I use my own since I have a more powerful gimmicky thingy to use and felt the one included was a little weak. Care must be taken when changing batteries so that the internal workings are not damaged (something I never had to worry about in the one I got at the flower show).
The effect is limited only by your imagination, so you can be very creative with this. It is very spooky especially in an area not so well lit (we turned down the lights in the demo to try and create a little of this atmosphere).
As mentioned in the demo, other versions of this are going for 4 times the price and although you get extra this and that's with the more expensive versions, really all you need is a little imagination and the prop and you should have a spooky routine made up before you know it.
Below is the sales ad for the Ultra Spook Light...
A pocket light, which a spectator can switch off and on like any light. However, the light can also be switched on and off secretly by the performer without touching it whenever he so wishes, even in a spectators hand. This model incorporates the latest technology to give you many more features, and permits you to do all the previous models could, and much more. Ready to use, with several presentation ideas.