I've discovered that I'm a sucker for a good Megalovania remix, but I think this one is my favorite. Spoiler: possible genocide route boss fight spoilers I choked up a little when Bonetrousle kicked in just before the end. I have a lot of emotions.
just had the idea of frisk always being unintentionally loud like papyrus, but for different reasons. frisk's volume control is fine. they just have weird hearing-they can hear just fine but their idea of 'loud' is. significantly louder than everyone else's. (also they'd have a really high pain threshold.) so they think they're only a little louder than everyone else, and besides everyone was telling them to speak up earlier anyway...what do you mean they're yelling? they're only as loud as papyrus and nobody tells him he's yelling! why does their throat hurt. (they are yelling.)
so apparently temmies have really low HP and defense. so low that if you attack one, hit it, and it survives, the narrator goes "How'd you do that?" this text was apparently believed to be dummied out until someone uploaded a video of it.
going by the rest of my headcanons, monster!frisk definitely does the accidental Loud thing. mostly because their definition of loud is loud enough that they're fine with how loud their magic can get. and that is. very loud. anyway the reason why i imagined some of that going over to canon frisk is because the idea of kind friendly frisk who is Loud living with very quiet grump chara is kinda funny. that and every frisk concept i've seen before is either mute or quiet, there doesn't seem to be any loud frisks.
oh no now i have fic ideas for that ship (valentines day flower shop shenanigans involving a very confused florist and frisk and chara buying flowers for asriel, asriel and frisk buying flowers for chara, and chara and asriel buying flowers for frisk...both asriel and chara know the language of flowers and are willing to help frisk with it so they all get bouquets for each other with coherent messages that confuse the cashier).
honestly that ship idea came from remembering a comic involving frisk repeatedly sparing flowey and when asked why by flowey, answering "because it makes you mad" with a grin and somehow...it turned into an actual ship for me
frisk makes golden flower tea for asriel and chara asriel retaliates with frisk's least favourite chocolates frisk offers to do his nails and does the most clashy awful glittery mess they can asriel has a thistle get up out of the ground and walk into frisk's room and so on ETA: golden flower tea is worth retaliation because asriel used to be a golden flower. frisk probably had a hatecrush on flowey, which just kind of. transferred to asriel.
Monsters picked up some really weird bits of human culture. Y'know, the basics: anime, basketball, quantum physics and the concept of burning in hell. Hell has filtered into pop culture enough that it's not necessarily a religious thing, but before the game started monsters were apparently talking about fallen angels. Whose damn garbage is filtering into the underworld, Dan Brown's?
to be fair monsters may have been on the surface at a time when angels were genuinely believed to exist. also, people throw out some weird stuff, and post-asriel coming to the surface, it's entirely possible that there's a group of humans deliberately throwing stuff into the underground-monster haters trying to bury them in trash, monster lovers trying to give them books, food, etc.
and of course the monster haters are unknowingly just giving the monsters free stuff-it just needs a bit of recycling they have created an entire culture of dumpster-divers with excellent recycling abilities ETA: selling garbage is probably actually a decent business in the underground-people with the time to gather up lots of trash sell it to people who have recycling equipment. bratty and catty may do that at their alley shop, or maybe they run the alley shop to sell the good stuff while the stuff that's only fit for recycling is sold somewhere else, or maybe they just leave the recycling-only stuff for other people.