“Praxeus” has the feel of an international conspiracy movie, in which intertwining events occur all over the world. It is a universe away from the claustrophobic spaceship settings of so many Doctor Who stories.

But it’s not a case of “never mind the alien pathogen, check out the scenery,” — there’s also a stark message about pollution.

Here are a few things to keep an eye out for, the next time you watch:

1. We are well used to the idea that Doctor Who’s thrifty production team can recreate almost any location using bits of Wales. But in order to create the beaches of Madagascar they travelled a little further, to the very windy Kogel Bay in South Africa.

2. In the absence of a special guest comedian, we have a very able replacement in Matthew McNulty, who plays spaceman Adam. McNulty is probably best known to British TV audiences as the gangster Sam from the extra-terrestrial superhero comedy drama Misfits. We’d show you a clip to prove it, but it’s really not for a family audience.

3. The Doctor reveals that she’s been investigating a talking cat in Ontario, which seems odd, given the amount of talking cat people she has met. But did you know that, according to at least one Doctor Who spin-off, cats are Gallifreyan?!

In fact, the Doctor Who Magazine short story “The Legacy of Gallifrey” claims that the word cat is an acronym for “calculating animals with tails,” and suggested cats were biologically engineered by Gallifreyans before they discovered time travel. Gallifreyan cats can also talk.

4. This is the last episode of Doctor Who worked on by special effects artist Neill Gorton – founder of Millennium FX. In an Instagram post, he revealed that part of their research into making the praxeus rash involved a hot glue gun.

He showed a couple of variations, noting, “One is the sculpted piece and then the second is dressed with a some hot glue threads. NOT applied directly to the face BTW — squeezed out on to a sheet of silicone first and cooled.”

He also left this neat sign-off on his years of service to monster making; “So sixteen years ago the first episode of Doctor Who I worked on was the Autons — an alien intelligence that inhabits plastic and brings it to life to kill people. This is my last episode and it's one about a space virus that infects people through plastic and kills them… Anyway, moving on.”

5. This isn’t the first time the Doctor has claimed to have more than one brain. In “The Bells of Saint John” the Eleventh Doctor tells Clara, “I'm from space and the future with two hearts and twenty seven brains,” although when she questions this, he does admit it’s an exaggeration.

6. Gabriela Toloi, who plays Jamila Velez, is the first Brazilian actor to make an appearance in Doctor Who. When her Two Girls Roaming partner Gabriela finally finds Jamila’s body and realizes she is dead, she calls her "melhor amiga," Portuguese for “best friend.”

7. This week’s moment of British slang belongs to Adam, who insists the Doctor try her antidote on him with the memorable phrase “stop faffing about.” It’s a term that originated in the late 18th century, partly in imitation of the wind, partly from the word faffle, meaning to stammer. 100 years later, the meaning shifted, and the verb faff came to mean dithering or wasting time. The ripe Yorkshire dialect added the "about" later on.

8. There is a problem with putting your alien henchmen in gas masks and hazmat suits, as the cast and crew found out on location. As James McKee lay on the floor, simulating unconsciousness, his breath created a vibration against the edges of the gas mask. A very familiar and distracting noise ensued, as captured in this clip:

9. Although the script was written and the episode filmed long before Covid, the airing of “Praxeus” in the early stages of the pandemic in 2020 did leave Doctor Who fans wondering if some time travel was involved to create such a timely story. But it’s not the only moment of synchronicity between production and broadcast.

Suki Cheng’s computer is seen running Windows 7 – in this unnamed date sometime in the very near future. But Microsoft announced that extended support for Windows 7 would end on January 14 in 2020. “Praxeus” aired just 19 days later.

10. Warren Brown – who plays the former police office Jake Hollis – is the actor with perhaps the broadest resume of anyone on the Doctor Who set (with the possible exception of Bradley Walsh). Not only has he appeared in a key role in a British soap opera – playing the evil Andy Holt in Hollyoaks, but he also played a policeman in Luther and Donny Maguire in Shameless. He is also a world champion Thai boxer who played one of Bane’s henchmen in the Christopher Nolan Batman movie The Dark Knight Rises, and has regularly appeared in Doctor Who Big Finish audio dramas, especially their UNIT spin-off series.

And this is him in 2009, appearing alongside Stephen Graham in the music video for Deadmau5’s “I Remember”. Talk about range!

Do you have a favorite moment from "Praxeus"?