This is actually a prop I made for a video. It is a flashing crystal egg. It is made from items bought at a local dollar store.
These are the parts, which are crystal eggs, regular fill-and-hide eggs, and these multicolor LED flasher key chains. Assembly is easy, and if you can't find these particular flashers then you can modify and use any other available flashers, like the electronic candles.
To make them fit inside the inner egg, I unscrewed and removed the end caps.
Then, I turned on the flasher and placed it inside the inner egg. Here the color-changing LED can be seen in action.
Then all that has to be done is snap close the inner egg, which opens lengthwise, and snap close the outer crystal egg around it, which closes crosswise. And the flashing egg is done.
As the multi-color LED flashes, it makes moving shadows and changing light patterns inside the egg itself. The batteries last for several hours and makes a good mood light, a decoration, or a video prop. The changing light makes it easy to dub in sounds and make it seem its' coming from the egg.
Here is the finished flashing egg next to its' components. It can make a good table decoration or other prop. A basket of these would be a spectacular sight.