Murders in the Zoo

After a curiously cutesy opening-credits sequence featuring Murders in the Zoo’s cast members mirrored with similarly posed animals, a quick tonal shift occurs, transitioning to perhaps the most gruesome film scene of its day.
Supernatural

This pre-Code offering packs a lot of story into its typically brisk running time, with several plot threads weaving together a (not always successful) tapestry of spooky and criminal doings.