The one where the Doctor blows up another priory...
The Fendahl finally manifests in human form, using the body of poor Thea Ransome, which it decides will look even better if painted head to toe in gold. And admittedly, Wanda Ventham does look utterly stunning in gold. I didn't think it possible for Wanda to look any more beautiful than she does anyway, but as a shining gold angel of death, she is magnificent. The rise of the Fendahl from flat on its back to standing upright is done really well too.
No sooner has the Fendahl manifested, it begins to soak up more life forces by killing its own coven, beginning with wily old Ted Moss, who's turned into a fendahleen sluglet. This does not go down well with Max, who is stunned that the creature he reawakened and hoped to control has now turned on the very people who worshipped it. Max's world is in tatters, and to make matters worse, he's looked the Fendahl in the eyes, which means certain doom.