It's the sort of question that's likely to cause an intergalactic, transdimensional dust-up among Whovians. But damn it, here goes: who is Doctor Who's greatest, most despicable, most terrible enemy?
We all have our favourites, of course. For my money, the creepiest are the Weeping Angels, the "quantum-locked alien killers as old as the universe itself", who first appeared in 2007. They stand as still as statues when you look at them, but then move quick as a flash when you're not looking. Their power? To throw you back in time so they can feed on the energy of your unlived days. Horrible!
But there are loads more to choose from, of course, such as The Master and the Cybermen, along with the shape-shifting Zygons, who gave Tom Baker's fourth Doctor such trouble - and a couple of dozen more, besides.
But really in my universe there is only one true enemy of the Doctor and they are the ones that scared the poo out of me as a kid in the 1970s and still do today: the Daleks. I mean really, what's scarier than a bunch of buzzword-chanting robots intent on galactic domination?
Every Doctor must face these frightful machines and in last week's excellent opener to the 5340th series (I may be exaggerating ever so slightly) of Doctor Who (7.30pm, Sundays, Prime), Peter Capaldi's 12th Doctor was looking like he's got a hell of a fight on his hands.
I very much like Capaldi's version after the fey, nonsensical hipster of David Tennant's 10th and the actually rather boring 11th Doctor played by pretty boy Matt Smith. I'm glad for Capaldi's slightly-menacing-old-man version of the Time Lord; he reminds of my favourite Doctors, Jon Pertwee and Baker. I like Capaldi's peppery Scottishness too, and that he, of course, reminds me ever so slightly of The Thick Of It's Malcolm Tucker.
But back to the terrifying Daleks. Last Sunday's season opener, the first of a two-parter, appears to be something of a Daleks foundation myth.
In a genuinely frightening opening sequence, the Doctor lands on a planet at war and (at first) attempts to help a small boy caught in a "hand mine" minefield (don't ask!). Then he learns the boy's name is "Davros" and, well, the Doctor left without saving him!
Is this kid the Davros who created the Daleks? You betcha. And in a different time, a dying Davros wants to face the Doctor one last time to confront him about this appalling behaviour way back when. And he does, his murderous megalomania notwithstanding, genuinely seem to have a case.
Certainly the Doctor seemed to hang his head in shame when confronted. Did he really do it?
I have no idea, but talk about gripping. Fortunately there were some terrifically silly scenes too, including the Doctor playing electric guitar on a tank in a medieval castle (he'd been invited to an "axe fight" ho, ho, ho). We also witnessed the unique sight of the Daleks zapping into oblivion both The Master, in the shape of mad Missy, and, gulp, the Tardis.
What the hell is going to happen tomorrow night? I have no idea. But the message is very plain indeed: the universe must continue to beware this army of buzzword-chanting robots with an appetite for destruction.
Exterminate, indeed.