Mad Monster Party?

a feature-length, stop-motion animated Halloween musical from Rankin/Bass, the studio which produced most of the animated Christmas classics (Rudolph the Red-Nosed Reindeer, Frosty the Snowman, etc.), as well as The Hobbit (1977)

the film features Boris Karloff as the voice of Baron Boris von Frankenstein and Allen Swift as virtually every other character. some character designs and voices are better than others, my favourites being Dracula, Mummy and Jekyll & Hyde. the set pieces are creative and detailed

i don't particularly care for the song-and-dance numbers, although the tap-dancing Dracula is amusing, but the jazzy, brass-driven score by Maury Laws in itself makes this a film worth watching. the story is interesting but ends rather abruptly, and the final product could probably have been cut down to about an hour without sacrificing anything crucial

imagine Bobby Pickett's Halloween novelty Monster Mash album transmuted into cinema, and you'll have a pretty decent idea of what to expect