For 'A Confederacy of Lanyards', the starting point was a Rat King.
A Rat King is an apparently real phenomenon where rats get their tails tangled, perhaps because the rats slept in a huddle and one of them had a tail dipped in something sticky. There is a lot of myth around Rat Kings, and speculation on whether they are hoaxes. There have been enough credible accounts, that we can be confident at least some Rat Kings are real... Probably.
Terry Pratchett's The Amazing Maurice and His Educated Rodents (now a fun animated movie), features a psychic Rat King as the antagonist. Pratchett in his practical way suggests that Rat Kings are made by bored and cruel humans who knot the tails together for fun. Given enough rats, and nasty people, it has probably happened.
From there, the idea for this one was to have a group of office workers knotted together with their lanyards. I would have liked to dip more into the mythology of lanyards, and the unnoticed talismanic presence of ID passes in our lives. But I got sidetracked into the mysterious social ritual around lifts, and the layer of taboos put on lifts in the last few years, and that shaped the direction of this story.
As an incidential detail, for me, the creepiest thing in this story is the idea of someone cleaning their ID pass every night.
Initially, I conceived of this as a monster story, where you would see the impact of my Lanyard King and then get the reveal at the end. Is there a government agency responsible for dealing with these rare but catastrophic breaches of lift etiquette? Could a pass simply expire, and break the union? Do they have psychic control over anyone who wears a lanyard?
That direction didn't quite work, and I realised it needed to be a story from inside the Lanyard King, with the personalities jockeying for control. From there, I needed to know their desires... And honestly, desire is often petty, so for the most part this union engages in low-level mayhem... One murder, rather than a spree. Rather than world conquest, they really just want to get their way and have a good feed and a sleep.
While I was writing this, by conicidence I was reading all of Alan Moore's Swamp Thing run, including the amazing sci-fi stories in the last stretch. In one of these, Swamp Thing's spirit lands on an alien planet, and grows a new body. Unfortunately, on this planet, the vegetation are sentient, and he fuses the terrified populace into a hive mind. As they say, there is nothing new under the sun.
One other kink in this story is the twist into a first person narrator in the last third, gently hinted at early in the story. There is a definite flavour of Lovecraft here, where the narrator is captured by the horror, as in The Shadow Over Innesmouth. But rather than end on a bleak and open note, in the spirit of mischief I had the narrator's plan collapse at the cusp of triumph... If, in the Lovecraft spirit, you can even trust anything they have said!
There is a saying that a good short story is like an egg, while a novel is a chicken. I did try to cram a few chickens into this egg - but, for the idea behind the story, perhaps that was appropriate...