Rhumbaphone! This is the only link I could find quickly but I can dig deeper. Seen them played live many times in the 1980s. Apparently only 2 in the world exist.
https://elfman.cinemusic.net/wp/forums/topic/rumbaphones-the-unsolved-mystery/
Monkeyshine, I hope you’ll look at this creator’s bio; he has a vast selection of Great Creativity!
In this case it’s a software synth, but Elfman is amazing.