Number 4 of my favorite Doctor Who stories: Snakedance.

This is a sequel to the first appearance of the Mara, in “Kinda.” Many people consider this one superior, and it’s easy to see why.

The Manussan Empire is an unusually well-written human society by Doctor Who standards. It’s complex, with a history as well as a present, and believable, taking pages from Britain’s own imperialist history and fleshing them out with interesting characters who are exceptionally well acted.

The Doctor is down to two companions, Tegan and Nyssa, and when (as here) Tegan is at the center of the story, she works extremely well, as opposed to the stories in which she’s on the sidelines carping about everything.

With Tegan in trouble, it’s up to the Doctor and Nyssa to solve the mysteries and save the day, proving Davison and Sutton’s contention that they work well as a team. And, as has been pointed out, there’s an unusual difficulty here in that the Doctor’s role is reversed from his usual. Here he’s faced with the task of convincing a society that the ancient superstitions they laugh off are real, when he’s usually doing the opposite. This doesn’t make as big a difference as it’s cracked up to — similar dynamics happen in other stories — but it’s interesting nonetheless.

The main attraction for me, though, is the Mara. Normally I’m not big on monsters with a psycho-mystical origin, as opposed to those that are straightforwardly physical and not just stupidly evil. But the Mara has two major edges here. First, it is both “real” — an entity that seems to act on its own, with the ability to lay dormant in a mind that isn’t thinking about it, and to pass from person to person whether they like it or not — and “psychic,” with qualities that relate to the mental states of those it possesses, rather than being a dull indiscriminate virus. And second, its avatar is a giant snake.

I fell in love with most of these episodes when I was around 10 or 11, and at that age I was still fascinated by snakes and spiders, and there you have the reason I was drawn to “Planet of the Spiders” and “Snakedance.”

It’s not that I didn’t pick up on the richness of the themes (at least the levels I was old enough to understand) or appreciate the performances or any of the rest of these episodes’ virtues. It’s just that there were aesthetic elements that were pretty much guaranteed to elevate a Doctor Who episode from an enjoyable or admirable one to a beloved favorite, and these stories had them nailed.

The only real criticism I’d have for “Snakedance” is that the Mara’s victims are curiously passive. While in “Kinda” the Mara stirred those it possessed to elevated levels of sensuality or anger or agitation, in “Snakedance” it seems content to collect them in a room or make them only slightly cranky. Presumably its tactics change as it senses opportunities for physical manifestation, from petty mischief-making to the instigation of ancient rituals, but it makes for a slightly duller scenario by comparison.