Crosspost of what I mentioned on Reddit:

Was this a sly deep cut prequel to 'Wolf in the Fold' ?

Given that both episodes cover the same terrain dealing with "monstrous, terrible evil" and " immortal, non-corporeal entities" possessing people?

'Wolf In The Fold' also ended with the entity jumping and taking over the ship.

('Wolf in the Fold' in the fold was written by Robert Bloch who also wrote 'What Are Little Girls Made Of?', the episode that introduced Korby and Chapel)