How do they react to a bittyfied Reader lol?
Horror: Oh. Oh no. You're...you're so small. He doesn't know how to fix this, he can't 'do science' anymore! The others can work on fixing it, then. In the meantime, he hates to admit, it's not so bad. It's cute, watching you eat a poptato chisp that's almost half your size, and it kind of tickles when you crawl up to sit on his shoulder. He is very, very careful when you're nearby though. He doesn't want to hurt you. He will, however, hide you in his ribcage and feed you chocolate chips.
Dust: No, this will not do. The world is too dangerous for someone so small, and you already made questionable choices when you were full size. You live in his hood now, tucked against his neck and peeping out to feel tall again. He’ll make you tiny chairs and a tiny table, and a tiny bed, and anything else you want. Spends a lot of time fighting Error for custody of your teenie-tiny self instead of trying to fix your size issue. (”it’s my turn, go wreck a universe or something!”)
Error: He’ll...well, he’s certainly not fussing, or mother-henning, or whatever Killer accuses him of next, but if you had to walk everywhere he’d be waiting forever, so it’s only natural to come up with something to carry you in, it just happens to look like an infant sling, it’s fine. And he’s not going to let you run around naked, so a few long sweaters and teenie leggings should work to keep you warm while everyone tries to reverse what happened.
Nightmare: Voted most likely to save you from Error and Dust when bones start flying. He won’t let you sit on him, you’d get stuck in the goop, but he’s pretty sure bitties have to stay near their people to stay healthy. This will be the one and only time he will allow you to come on a raid. They’ll hit up a bitty-bones AU and let you pick out...whatever you need at that size. You’re an inconvenience, but a cute one, running around on his desk like that. In the end, you end up more like an evil villains' lap-cat. Hope you like pets.
Killer: Ok, so hear him out. You can’t steer the remote control car, but you can fit in it. So do you trust him? No? Ok, that’s fair. He supposes he’ll help get you back to your proper size, but he’ll take plenty of breaks to help you with very serious scientific inquiries like “what is it like to bathe in a mug of jello?” and “How high will you bounce on a trampoline with a skeleton as a counter-bounce?” You’ll get the least amount of coddling from him, but it’s nice to at least pretend you have a modicum of independence.