In the bug cursed au Bill kicks off weirdmageddon and is immediately attacked by a tiny moth!Ford wielding a sword. This is really weird and also pretty funny at first, until moth!Ford starts actually kicking his ass and also a caterpillar?? Is also there?? Attacking him?? Where did these Actual Bugs get the ability to harm him and do parkour
All his henchman see is Bill desperately swatting at the air and somehow losing his shit to nothing. Then Weirdmageddon ends bc Fords got great speed buffs and Stan's been practicing kiting for the past decade and has obscene damage output
Bill starts bugmagedon then gets surprised he's attacked by moth!Ford and his new ability to fight bug gods through sheer physical violence. And also a bunch of other bugs are also there, successfully kicking his mini form's triangular ass.
The witch comes out of her hut, see's a weird red dome encompassing the car she can't get rid of because she turned the owner into a worm and by the time she realized that having it around might be a problem the trunk was full of bee's (she's allergic to bee's), turns around and goes back inside.
(Bugmagedon is for bugs only. Bug sized portal made by hyper intelligent bugs means bug sized cipher and bug sized weirdness barrier. I don't make the rules (yes I do))
Bill and his henchmaniacs get taken down in record time because Ford had to Dark Souls Bug Style for the last week and got crazy good at perfectly timing dodges and had to fight ten different bug gods before he found his bro, The Evil Velvet Worm God, then had to fight a bunch more bug gods because Stan thought it would be a good bonding activity/dragging his feet about being human/showing off his bug civilization to his bro/teaching Ford to be a bug properly/Stan got hungry and bug gods make the best snacks (Never mind all Bug Gods used to be human. They're bugs now. Stan eats bugs). Stan's likewise been spending the last 7ish years living Bug Dark Souls and clawing his way up to the top of the bug food chain and fighting off bug rivals and has like. Three or four bug wives who aren't bug gods but are hella powerful. One of which is the queen bee and is totally willing to send her soldiers to sting Bill to death.
Its Dark Souls with moth!Ford doing flips, dodges, fast sprints, spin attacks, double jumps, etc at Bill floating around in front while in the background Velvet Worm! Stan is eating his way through the henchmaniacs in snippets you see over the course of the fight. Now and then Stan pops in to spit slime at Bill.
To any human it looks like bugs swarming the hell out of a single dorito chip.