These are just the facts. On July 22, 2013, Catherine, Duchess of Cambridge, gave birth to her first child, Prince George. Two weeks later, an enormous “fatberg” was discovered in the sewers under London. A hellish fifteen-ton lump of cooking fat, congealed with diapers, wet wipes, sanitary towels, and condoms. In videos taken by sewer workers the thing crawls over the walls and ceilings of the grand Victorian drain, its tendrils puffing out from the monumental central mass. A mound of fat the size of a London bus, glistening death-pale in the torchlight; fungal, a saprophage, its terrible bulk blocking off the normal hygienic flows of piss and shit. It took three weeks for the utility company Thames Water to fully repair the drains.

On September 8, 2014, Catherine announced that she was pregnant with her second child, the future Princess Charlotte. Seven days earlier, photographs of another London fatberg had been released. This one was the size of a Boeing 747 jet, messier and more coagulated than the first: its surface looked like rubble, strewn with pickled tennis balls and rotting fruit and plastic cartons, an eighty-meter landscape of rejectamenta.

On September 4 of this year, Catherine announced her third child. It took eight days. By September 12, a titanic fatberg had once again been found under London. It’s still there. It’s under my feet as I write. Workers are doing everything they can, blasting it with boiling water at high pressure, but the thing is almost immovable. Nearly ten times heavier than the first, longer than Tower Bridge: 250 meters of concrete-hard fat and waste, a sprawling, city-rending, apocalyptic terror of everything nobody wanted to see again. Your shit-smeared shame, the uncomfortable things you flung into your memory hole, that private Lethe that flows from a clean and tiled little room in your home—it’s back. The repressed always returns. You built a monster.

The fatbergs are evolving.

The fatbergs are evolving. They keep getting bigger and tougher; from what the workers battling them have said, each one smells worse than the last. Not the usual familiar stink of timeless bodily waste, but something far worse. The smell of decaying dishcloths, sour mayonnaise, the uniquely putrid combination of detergent and grease. The soap is more foul than the shit. Why? People are still pouring their cooking fat down the drain and flushing soiled diapers down the toilet, but no more than they always did. The only conclusion is that the fatbergs are growing of their own accord. Whatever intelligence is directing them, it’s getting stronger. It’s building its forces. It’s waiting to burst out from the hidden sewer-dimensions, and conquer the world of sunlight. The fatberg lives.

It will happen slowly; by my calculations, it will take just over eight months. The first victims will be in the sewers. Above ground, ordinary life carries on, and London grumpily ignores itself through eight million busy stares. A few short meters below, the terrible Thing awakes. After weeks of battling the fat-monster, watching it slowly recede under water-jets and shovels, the Thames Water technicians with their rubber boots and white overalls—darting, pale, fragile creatures in the seething, stinking darkness—will hear a rumble. The fatberg is moving. Like a lava flow of rancid fat, crusted with household detritus, grinding towards them, slow as a steamroller and just as unstoppable, it moves. The workers try to run, splashing through effluent that grows denser and paler as the rolling fatberg approaches, until they put their feet down and feel them sink slurping into a mess of compacted fat, grabbing them tight around the shins and pressing against the bone. In the last moment, as the fatwyrm descends, they can see in its roaring edge two bright points that could be eyes, and an inhuman cavity filled with what could be teeth. They suffocate in its bulk. They are carried along in its path. More mass for the fat.

Walls of streaky fat plunge around the gates of Buckingham Palace.

The fatwyrm leeches out through gutters and drains. Greasily languid tentacles feel their way into your dishwasher and extend, smashing crockery, splintering glass, finally blowing the door open and crawling along your kitchen floor in an explosion of filth and steam. Outside, a thin veneer of grime seeps down Oxford Street, a trickle of murky discarded oil that sends vehicles skidding at high speed: up onto the pavement to smash the pedestrians into bursts of viscera, into each other, crumpling into readymade barricades. When the monster rises, nobody can hope to escape. The first fatberg was the size of a double-decker London bus; this thing sweeps up the buses in its churn. In the City of London, the weightless glass skyscrapers seem to drip with slime, sweating thick, viscous trails down their flanks. In the outer reaches of the city, the ordinary garbage that piles up by railways sidings, in abandoned industrial lots, in fallow fields strewn with coffee cups and shredded plastic bags and all the scattered nothing-product of the post-industrial age—every unneeded thing seems to tumble more purposefully in the fetid wind. Its master has arrived. The spirit of the forgotten. The monster of the disposable. The great and jealous god whose name is Use-Once-And-Throw-Away.

The shit-flows, forced from the sewers by pullulating streams of fat, are forced out into the river. The Thames bubbles, a blackened wash of turds. By its banks, a shapeless marshmallow of roasting grease and baby wipes rears up to gnaw at Big Ben. Puffy globes bubble around the base of the tower, and it falls. And not far off, the vacuole is forming. Walls of streaky fat plunge around the gates of Buckingham Palace. And inside, in terror and incomprehension, the god is being born.

The fatwyrm is made of our shame and our rejectamenta. The things of commodity capitalism are autonomous and alive, until we are done with them, and they become junk. And the seepings of the flesh too. Anything that discharges itself from a human body is considered to be shameful. There’s a horror of the things that leak out: they violate the idea that we are whole and impermeable, they connect us in streams to the sordid and undifferentiated body of the earth. Shit is disgusting. Piss, sweat spittle, pus, cum, menses. There are only three exceptions. First, tears, which pour out of the eyes. They are not disgusting: they carry meaning and emotion, they are not quite dead matter. Second, words, which pour out of the mouth. They ought to be the most repulsive of all, but few people are horrified to see a mouth scrunch and grimace and hoot, unless it’s speaking a language they don’t understand. And third, other humans.