The toy is mostly hollow with a weight (grey) at the bottom so the center of mass of the toy is lower than the center of the spherical base of the toy. When pushed over, the toy wobbles for a few moments while it seeks the upright orientation.
The pink hammer acts as a pendulum and strikes the red vibrating wires of different lengths to create musical sounds.
This video is made based on the patent:
https://patents.google.com/patent/US3...