Dad and Onion Head's...Head.

My dad worked on both the first Ghostbusters movie, and a live-action stage show that was produced for Universal in the early '90s.

 

My dad was a multi-faceted, talented special effects guru. He was an artist and sculptor first and foremost, but he was a tech wiz who created all of the servos and motors inside. His many talents allowed him the flexibility of doing a lot of research and initial prototypes at home, which may (or may not) have been the case here.

Done