Okay apparently the only attraction ever to feature anything from The Black Cauldron was the Cinderella Castle Mystery Tour in Tokyo. Its a lot scarier than most Disney attractions that's for sure! Unfortantly it closed in 2006.
This attraction had a audio animatronic of the Horned King! And yikes is it impressively scary!
Here's part 2 of the tour which features the Horned King; you can find part 1 from here too if you'd like to watch the entire attraction. Its quite a dark attraction so you won't be able to make out some things. I would suggest full-screen viewing. Its in Japanese but the video description's detail what's going on.
Click Here.
That Horned King is AMAZING! Its quite an older animatronic too I think. But seriously... very impressive indeed!