It’s true — you really can find anything (except maybe LEGO) in thrift stores. When [thecowgoesmoo] picked up a Mr. Christmas Symphonium music box one day, they knew they wanted to make it play more than just the standard Christmas and classical fare that ships with the thing.
This is a companion discussion topic for the original entry at https://hackaday.com/2024/01/12/all-i-want-for-mr-christmas-is-some-new-music/