A good bit of classic occult/folk horror Who, with a bit of an eldritch flair. Nothing especially groundbreaking here in terms of plotting or villainy, and the plot drops off sharply for a bit while the Doctor and Leela go try to investigate the creature's planet of origin in the TARDIS, but it had some great design work, some fun side characters, a nicely unsettling atmosphere, and some good Doctor-companion relationship. I enjoyed it immensely.