Colour changing record
A "vinyl single" record is inserted into a folder and a ribbon threaded through the central hole. When it is pulled out it has changed to the colour of the ribbon.
This is repeated twice more.
The folder is shown to be totally empty.
Now that vinyl is coming back into fashion this will be a topical item - however it's also a collectable vintage trick. The records are actually cardboard replicas and the effect is designed for stage use. Complete with records, folder and instructions.