The head will shake when you tap the image or change the brightness.
It becomes a digital signage that swings across the front of the device.

https://play.google.com/store/apps/details?id=asia.remix.bobbleheadfree
Ad-free paid version. Available on a wider range of devices.

If you press and hold the image, you can move, enlarge, reduce, or replace it.
Furthermore, you can adjust the spring properties, brightness changes, and background color.