The name of the product really says it all - these are silly, which is precisely the reason why children seem to love them so much.
If you are not familiar with these, they are a very popular item right now and are basically rubber bands that come in a variety of different shapes, such as the Princess Pack (magic wand, castle, crown and other things you think of when you hear princess.) They are worn as bracelets, a hair tie or even can be used just as a rubber band.
When they come off, they go back to the original shape.