The Devil Rides Out (1968, Terence Fisher)

Another film with a dense, confused audience-surrogate character: pilot Rex (Leon Greene, a Holmes in The Seven Percent Solution), who meets his old buddy Christopher Lee (same year as Dracula Has Risen From The Grave), then goes searching for their missing friend Simon. They find that he has joined a posh group of satanists (Britain was too polite for all this – the satanists reel in horror when their leader kills a goat), and try to rescue him through frequent use of crosses. Rex falls for satanist Tanith (Nike Arrighi: Day for Night, The Perfume of the Lady in Black) so they attempt to rescue her too, pursued by the Victor Garber-looking cult leader Mocata (Charles Gray, another Holmes in The Seven Percent Solution). Satanic possession and kidnapping follow, then evil is defeated in a very Christian ending.

Lee uses the interrotron on Simon:

Giant spider terrifies little girl: