Originally Posted by Phoenix Lazarus:
“What a weird moment the vicar becoming a semi-ape in Ghost Light was. What was that all about? Are we to assume it had been done by the main villain (Silas? I forget his name). If so, how did he do it? Why did he do it, too? Was it just an experiment on his part, or was it because the vicar was antagonising him. The humour of this seemed rather out of kilter with the generally serious nature of the adventure-although having said that, I found it oddly creepy and disturbing for a humorous incident, along with the later scene of him petrified and presumably dead in semi-ape form in the glass case, like a stuffed animal.”
Ghost Light was all about evolution. The entity Light was studying and cataloguing life forms, and found that Earth was always changing, so he set up an experiment to study evolution. While Josiah evolved from some kind of animalistic form into a more human form, Control was kept isolated as a, well, experimental control.
Yes, it was Josiah that forced the vicar's 'devolution' into an 'earlier' form, much as he reverted the Inspector all the way into primordial soup. Mostly because he needs to be seen as a nasty villain, but partly also to mock the vicar's disbelief in evolution. And probably to show off how he'd evolved - they were so 'backward' compared to him.
And yes, it is all very silly and doesn't hold up to a lot of scrutiny. I can see why some people can't be bothered with it, but it was smart and unpredictable, and they tried something very different and got a lot of creepiness mileage out of it.
