Swellhead

A 2007 short story by horror writer Kim Newman, part of his "Diogenes Club" sequence of stories featuring Seventies psychic detective / glam-rock fashion enthusiast Richard Jeperson. Unlike the other stories in this sequence, which are set around the 1960s-1970s, this one transplants Jeperson to the modern day.

It's the new millennium, and strange things are afoot on the long-deserted and distant island of Skerra, located at the point where the borders between Britain and Iceland become vague. A survey team has disappeared, but not before sending back an unsettling discovery -- a bloody jacket, 1970s style, covered in the blood of two men; long-retired psychic detective Richard Jeperson, and Sewell Head, a humble sweet-shop employee and pub quiz champion. Problem is, there's only one jacket like that in the world, Jeperson owns it, and he's certainly never fought Sewell Head to the death while wearing it. Convinced that the appearance of the second jacket means that bad things are afoot on Skerra, he is convinced to come out of retirement and joins Head and others -- including Detective Sergeant Stacy Cotterill, sent by her boss (and Richard's old friend) to keep an eye on him, and pompous government scientist Adam Onions -- on a reconnaissance mission to find out exactly what's going on. Realities are beginning to weaken and merge together, however, and a dastardly evil -- Swellhead -- is rearing it's head to finish a battle that may never have began...

Tropes used in Swellhead include:

Alternate History / Alternate Universe: The story is about what happens when one of these begins to encroach on our reality. Hint -- bad things.
- In a meta-sense, as well as the alternate universe that forms the crux of the plot, the story also references and hints at several other Alternate Universes and Alternate Histories Kim Newman has written or co-written, including Anno Dracula, the Back In The USSA stories and an as-yet unpublished sequence in a Nazi-occupied Britain. Not to mention the Temps Shared World; a very different Sewell Head first appeared in "Pitbull Brittan", Newman's contribution to the first Temps anthology.
Creepy Souvenir: Swellhead's lair includes a hallway where the heads of his enemies are displayed like hunting trophies.
Different World, Different Movies: The Elaborate Underground Base contains books, music and technology from the Alternate History it's originated from -- such as the novelisation of 2001: A Space Odyssey by Stanley Kubrick and Ray Bradbury; however, this serves to weaken the perspective of those inside it and get them to accept its reality. At one point, Jeperson begins to think he's going senile because of it.
Disco Dan: Both Richard Jeperson and Swellhead, in different ways; Richard, in his 'groovy' seventies gear, is completely behind the times -- however, he's cheerfully accepted it and is comfortable in his niche. Swellhead is also behind the times -- he holds all pop music since about 1973 in contempt, which comes back to haunt him -- but one of the reasons he's doing what he's doing is to force everyone to like what he likes.
Doing In the Scientist: Adam Onions. Quite literally.
Elaborate Underground Base: One seems to have appeared out of nowhere under the island of Skerra: Turns out, it actually has appeared out of nowhere; or at least, an Alternate Universe.
Evil Gloating: Subverted with a lampshade; Swellhead claims he's not an inadequate who needs everyone to understand his plan. However, Jeperson is clever enough to figure it out anyway.
Genius' Sweet Tooth: Sewell Head has a fondness for chocolates and sweeties. The more manic his consumption becomes, the more evil he becomes.
Genre Savvy: The villain, Swellhead, is correctly convinced he's a Bond-style villain and uses his Reality Warper powers to make this the case. Unfortunately for him, he inadvertently uses this to strengthen Richard Jeperson's own power; every villain needs a hero worthy enough to challenge him, after all...
Grand Theft Me: A particularly insidious example; Sewell Head is gradually taken over by Swellhead, an Alternate Universe version of himself who happens to be a Bond-style supervillain. He then proceeds to do the same to other members of the party; it's implied that everyone there in one way or another has an alternate self who is somehow involved.
He's Back: The entire story is Richard Jeperson coming out of a twenty-five year retirement to sort out his messes. He initially lampshades this, insisting that this isn't going to be "Richard Jeperson Rides Again". He gradually comes to realize what a mistake he made in retiring, however, and the ending all but states outright that Richard Jeperson is back in the game for real...
It Is Pronounced "Tro-PAY": Adam Onions constantly insists that his last name is pronounced "Oh-NYE-Ons". Swellhead eventually settles his hash... by whacking him with a laptop computer.
Magic Versus Science: An old argument between Jeperson, who takes the magic side, and Onions, who takes the science side. It's played with, however, in that Jeperson isn't exactly 'anti-science' -- he just opposes Onions' particular brand of blinkered, self-serving 'practical applications' (i.e. how-can-I-exploit-this-for-personal-gain) approach.
Mutual Kill: It's implied that the final conflict between the Alternate Universe versions of Richard Jeperson and Swellhead ended in one of these.
Obstructive Bureaucrat: Adam Onions (It's pronounced Oh-NYE-ons), a pompous little man who's so consumed by using his special scanners to explore every single tree he comes across that he completely fails to notice that he's gotten trapped in a particularly nasty forest. To read; he's so busy looking for evidence of ghosts that that he doesn't realize -- or accept -- that the entire structure he's in is one large ghost. Because he and Richard have a long-standing emnity, he's also quick to smirkingly dismiss anything Jeperson says. This comes back to bite him hard.
Popular History: In-universe; at one point, Richard Jeperson alludes to petrol shortages and power cuts, television stations ceasing transmission at 10.30pm and a terrorist bombing campaign against the mainland United Kingdom occurring in 1973. One of the other characters immediately declares that none of that happened, he's delusional and confusing The Seventies with World War Two. All of that, of course, very much did happen; because she's an idiot, however, Jeperson is more amused than offended.
Reality Warper: Sewell Head / Swellhead. His supervillain plan is essentially to recreate all of reality inside his head.
Retired Badass: Richard Jeperson. Partly deconstructed, in that it's frequently pointed out -- and he increasingly comes to realize and accept -- that if he'd stayed in the game rather than retiring, things would have been a lot different, he could have made a lot more difference, and people might even still be alive. The ending implies He's Back for good.
Smug Snake: The smarmy New Labour civil servant "Really-A-Good-Bloke" Rory.
Wicked Cultured: Parodied; the villain is massively intelligent and knows pretty much everything, but a) his cultural leanings are decidedly cheesy (he likes Burt Bacharach, and has muzak versions of MOR songs playing in his Elaborate Underground Base) and b) he is actually defeated by his lack of knowledge of the younger generation's pop culture.