Disclaimer: Anything you recognise, I don't own – characters as Pratchett's and Gaiman's, and Westlife belong to themselves.
"Every year! Every bloody year, Aziraphale!"
The book-hoarding angel looked slightly hurt by his counterpart's outburst. "Well I already have the outfit. And it is a rather convincing one," he added.
"But it's not the point! You're meant to dress as something scary, something that you are not in everyday life!" The demon resumed his pacing around the small area of floor space not covered in towering heaps of books. He nimbly dodged a falling tome dislodged by his elbow. Aziraphale stopped its descent and replaced it on the pile.
"I seem to remember you turning up as a demon before, Crowley," he remarked absently. Crowley glared behind his sunglasses. He hadn't thought the angel would remember that time in 1979.
"Well technically, I am actually a fallen angel, rather than of demon stock, though I do the job of a demon," he replied, smug with the loophole he had discovered. Aziraphale gave him a look that said 'I'm not buying any of it'. Crowley scowled; after only a few thousand years in his presence, the angel was beginning to use his own tricks against him. It wasn't on.
"I don't see why you have to go anyway," continued the angel, ignoring the silently fuming demon – sorry – fallen angel. "I would have thought that the entire holiday of Halloween; suitably commercialised and celebrating wickedness, is evil enough without an actual demon presence."
"Well it's not in the job description," began Crowley.
"I would have thought not, considering trick or treating only began in America in the 20th century."
"Must you be a walking encyclopaedia? But, it helps me fill my quota of turned souls. It's ridiculously easy on Halloween," the demon sighed. "Lots of greedy kids, lots of irate house-owners, worried parents…it's almost too easy to provoke arguments and violence that continue their effects long after the night…You don't have to come though, angel."
"With you corrupting the entire country? I think I do," replied the blonde haired creature, shifting a pile of paperbacks so that they hid the till more effectively.
Crowley slumped into an armchair that appeared from nowhere. The sleek black leather looked out of place in the cluttered shop, and with a wave of his hand, Aziraphale re-upholstered it. In a charming plaid fabric. The demon rolled his eyes, stood up again, and vanished the chair without a word.
"Alright, fine. I'll pick you up at five, angel." Crowley swept out of the shop without waiting for a reply, which was possibly a good idea, considering Aziraphale had unearthed an ancient teapot and was engrossed in making a cuppa.
Possibly. It's hard to tell behind those sunglasses.
Five o'clock arrived, as time is wont to do. It found Aziraphale in his bedroom, tugging nervously at his white robe. He had unfolded his white wings, and fashioned a halo out of tinsel and wire. All in all, he looked very angelic. Just right. And Crowley was late as usual. However, that didn't explain the twinge in his stomach. Something seemed different about tonight, but he couldn't put his finger on it. Oh well, he would handle whatever mischief Crowley could cook up. Through the window he heard the sound of the Bentley drawing up, and with one last tweak to his halo, went downstairs.
Contrary to popular belief, angels don't actually have halos. However, after nearly fifty years of six year olds asking if he had lost it, Aziraphale had relented and made his own.
Aziraphale slid into the passenger seat of the Bentley, begged, borrowed and stolen from an American diplomat by the demon. It was almost identical to the original, down to the fact that no cassette could remain the way it was published. This one was worse however. Handel, Bach and even 'Best of Queen' automatically metamorphosed into 'Westlife – The Greatest Hits: Volume 1' after two weeks. Aziraphale generally ignored the dubious origin of the vehicle in favour of being able to travel in comfort and style.
The angel glanced at the demon next to him. Apparently he had taken Aziraphale's comment and ignored it – he was dressed as a demon, almost like the devil himself, complete with red cloak, red and black waistcoat, tight black trousers, pointy boots, and red horns, as well as the ever-present sunglasses. He looked good, thought Aziraphale, and then dismissed the thought. Of course he did. Crowley was a demon, after all, creatures renowned for always being stylish. He was quite pleased that they matched though. Only for the symmetry, of course.
The demon pulled up on his chosen suburban neighbourhood in Surrey. This was one advantage of getting a lift with Crowley, mused Aziraphale. He didn't have to search the country for increased demonic activity; he just had to follow his friend.
"This way," said Crowley, striding away from the car towards a field. Aziraphale glanced over his shoulder at the groups of children in costume, ringing doorbells, and jogged after the demon heading in the opposite direction. They reached the hedge which Crowley threatened until it bent backwards on itself, causing a gap just big enough for one occult and one ethereal being to pass though. Aziraphale muttered a comforting word to the hawthorn, but couldn't help feeling slightly suspicious. Surely Crowley's grand plans for the evening had not been to frighten the hedgerows of southern England. He was right.
"Okay. Take it off."
Aziraphale merely stared at his friend of the past few millennia. He knew they had become closer after averting the Apocalypse, but this was a little too – uh - friendly. "Crowley-" he stuttered, "I really don't think-"
"Oh come on, Aziraphale! Take that goddam dress off!" Crowley began unbuttoning his waistcoat, revealing the red silk shirt underneath. Aziraphale flushed almost the same colour.
"If you don't start undressing, angel, I'm gonna do it for you," added Crowley, pulling off a boot. "If you don't get a bloody move on we're going to freeze in this field."
"That's technically impossible," Aziraphale managed to squeeze out.
"But I am a hot-blooded creature, Zira, so a field in an English autumn is not my ideal place for stripping."
"Then why here?"
To the angel's surprise, Crowley laughed. "I'm thinking off the kids, Zira. Don't want to scar them for life. You must be rubbing off on me."
Was it his imagination, or had Crowley emphasised that last phrase? Aziraphale was startled out of his reflection by the feeling of hands tugging on his hair. Crowley, he realised, was muttering to himself, "get rid of that…honestly, couldn't you have found something more realistic?...Tinsel?...I thought you said that was demonic anyway, 'cause it's always in knots when you come to put it up…" He didn't appear to want a reply. Aziraphale stood frozen as his friend absently smoothed a golden curl back into place, but the feeling of frigid October air snapped him back to reality.
He yanked his robe closed, gaping like a fish at his demonic counterpart. "Crowley," he gasped, trying to ignore the sight of his 6,000 year old friend in nothing but a pair of tight trousers, "we can't! There must be some sort or rule, or – or – something!" The angel was now whispering shrilly, despite the complete absence of life in the field. Crowley cocked his head, confused.
"Well I know it's a bit strange, but it's Halloween! They're not gonna think anything of it," he reasoned. Aziraphale resumed his fish impression. "It's not like they're gonna make you fall for it! Live a little, angel."
Crowley's face had hardened at not getting his own way. Aziraphale noticed, and snapped, "just get dressed, Crowley."
"That is what I was trying to do," he replied, voice dripping with sarcasm. "Only someone won't take his off!" Crowley shivered slightly, and Aziraphale softened.
"I'm just not sure it's right, Crowley," he began, his voice so understanding it was almost patronising. "It's not just me I'm worried about, I'm sure Lucifer would have something to say, and I couldn't stand you getting hurt. We're walking on thin ice anyway with the Arrangement, especially after the Apocalypse."
Crowley sighed, annoyed. "Not that I'm not glad you care about me, angel, but I can't see the big man downstairs getting involved over a Halloween costume."
Aziraphale had moved from goldfish to guppy impersonations. "Halloween costume," he echoed steadily.
"Yeah. Switching costumes, mixing it up a bit this year. To be honest, I wouldn't mind playing at being an angel for the night." Crowley looked ever so slightly wistful, and Aziraphale was strongly reminded that it was around this time in the year that the other being fell. Of course, that was before the Gregorian calendar was invented.
"Why, what did you think I meant?" Aziraphale flushed brightly, visible even by the weak moonlight. Crowley grinned as understanding came to him. "Oh, I see," he smirked, "well there may be time for that later as well, angel. I must admit, I quite fancy the idea of you in a devil's outfit…"
The demon spun on his heel and walked back towards the hedge. Aziraphale quickly gathered the rest of Crowley's clothes, and started after his friend. The fallen angel back over his shoulder at his friend, and beckoned lazily with his trident. Aziraphale quickened his step.
At least, the human view of the devil. People always seem to forget that he is of angelic descent. He actually bears a passing resemblance to Aziraphale, only without the tweed.
Quite why this impression has been formed is unclear. Many demons have even less fashion sense than Aziraphale. Sweatshops are demonic inventions.
And probably unnecessarily, but never say a demon can't work the sympathy vote.