I watched this film around 10 years ago on TV with my dad and brother, at least more than once. My brother remembers it too but not the name, and my dad has no idea.
It’s set in the middle ages in some sort of kingdom, and this evil ‘uncle’ with slick black hair gives the princess a music box as a present. Inside is a prince I think but he turns into this clay blob in some sort of claymation scene, then as the film goes on becomes a monster, growing and growing and destroying the kingdom and capturing the princess. The film itself seemed old, made in the 70’s/80’s maybe??
This is all I remember which is really frustrating. I have spent hours looking on Google and YouTube for it but as i can’t remember the name or much of the plot it’s very difficult. Any help will be much appreciated, thank you