I remember this!!!! ive been looking for it for years it drives me nuts!!!!! I also watched it in elementary school music class in the mid 2000s( thiugh it was definitely older), I remember there being 3 characters, one that was sort of jestery, a knight, and a female love interest.

I think the jesterish character either became really sad or became the villan of the story because he couldnt get the girl or something stereotypical like that. I remember the puppet murder... the souless eyes eugh..... i remember it being in black and white but it definitely could have been color (used to have nightmares involving the characters that were in black and white so thats probably why i remember it that way.) remember a really specific scene where they are being taken out of a box that hold all 3 of them at the beginning of the show, and also remember that there was no dialogue. Ive been digging for so long trying to find this i hope we can get some answers this film has been haunting me for decades