Halloween // Looking for ideas

Found 2 of them at a second-hand store. The white cap has an interior diameter of 3/4 in. Turns at about 3 rpm. Seems like I could use for something creepy, but I'm currently drawing a blank.

https://preview.redd.it/d68rvd795i271.png?width=4032&format=png&auto=webp&s=7ebc295dacc604298e3adcbe381bb6be5c7e4ee2