Yeeeep, both of the skeletons have masks up with pretty much everyone. Papyrus drops his a bit to bicker with Sans, but other than that?
I noticed a thing about the main six characters and their... motivations? Alphys and Papyrus are both motivated by wanting to be liked/loved, respected as being competent and cool. They lie to themselves and others to make themselves more appealing (or what they think is more appealing). Undyne and Asgore are motivated by wanting to protect their peoples' lives, hopes, and dreams--in that order. They have problems with tempers and doing things they later regret, and procrastinate admitting that they don't want to fulfil certain dreams (Pap in royal guard, ever breaking the barrier) Toriel and Sans are motivated by wanting to protect the family they have, dwelling in the small moments of home and hearth and humor. They neglect the lives of people in the big picture for the sake of the few they care strongly about, keep secrets from those few, and are late to decide to actually act to protect those loved ones. Neat parallels between them all.
speaking of patterns and the six main characters, even though it works narratively and i wouldn't want to change the story for this, my brain can't help but be bugged by the fact the Six Main Characters and the Pacifist Route Main Bosses aren't all the same characters. like, it feels like there should be a pattern but it's broken. mettaton is not one of the six main characters, and alphys and sans aren't bosses in the pacifist route.
Spoiler Not gonna lie, the biggest question facing me as I consider trying to roleplay as Alphys is figuring out what the heck magic powers she has. As a Lost Soul she uses some of the powers that Mettaton did, the bombs and robots, and in the first quiz we learn that robots are made of "metal and magic." So I'm under the strong impression that the electricity parts of the magic Mettaton wields are Alphys', somehow. Like Toriel's fire dies if you kill her, so Mettaton might lose access to those powers if you killed her? We know he's functional in endings where she ... disappears ... so it's not like his body would completely shut down. I think that's part of why fandom under-represents her, though. The ways the different characters fight and use magic and interact in the battles gives insights into them. But Alphys and Mettaton are swapped in that regard.
Spoiler i wonder how she'd give him those powers. 'cause, like, toriel's fire is solely controlled by toriel, the owner of the magic creating it, whereas mettaton's electricity magic is pretty clearly not controlled by alphys. and maybe i'm wrong here but it feels like there has to be something special that gives her powers to him as something he can use however he wants to. but that's intuition, not anything based on solid canon.
Spoiler Magic in Undertale is weird sometimes. Lesser Dog, Greater Dog, and Endogeny seem to have their own bodies shooting their attacks... but not all dogs do. Doggo, Dogamy and Dogaressa, (and Undyne) all have magic attacks that seem to be literally the weapons they carry around (or summon). Mad Dummy summons dummy bullets that shoot their own bullets, and they're apparently semi-sentient enough that he argues with them and fires them when they don't do well enough, then summons up more robotic ones to do his bidding. And then a knife. And then he's out of knives, as though he's actually summoning them from somewhere instead of creating them. Somewhere... like the interdimensional boxes accessible through a cell phone? So if Mettaton is somehow using Alphys' magic instead, it would be because it's her magic that helped power his body. Like Toriel's magic powers her fireplace... except that, unlike the fireplace, Alphys has been upgrading Mettaton's body to make it more self-sufficient, running on batteries instead of her magic. And this is still stuck in the land of headcanon. -_-
Spoiler lesser dog, greater dog and endogeny are the quadruped + dogspeak dogs, but doggo and dog marriage are bipedal + normalspeak dogs, which may be why their attacks work differently. different subspecies within a species, something like that. mad dummy is just... bizarre... that way. her magic helping power his body makes sense as a way for him to get her powers. it definitely makes it so not just any monster could commandeer any other's powers, and so it is also the kind of thing that mettaton and alphys wouldn't have deliberately planned on.
Spoiler Ooooh that is a good point about the bipedal/quadrupedal difference to the dogs. I referenced Mad dummy because they summon all those minions that summon their own attacks, and Mettaton does a similar thing, so I was wondering to myself whether that might be a ghost thing they're both doing. Problem is... lost-soul!Alphys uses it too. Legs, disco, heart-to-heart, essays... those are only show up in the MettatonEX fight.
I don't know how to unattach a file. I learned a thing, if the thing is learning that I don't know a thing.
I saw a theory that Mettaton's heart-to-heart thing is related to Frisk's magic thing. Specifically, Mettaton's soul is point-down, and after Frisk's soul resonates with Mettaton's it rotates to point-up. Also Alphys has notes on her desk, with what appears to be a dead human and a monster soul, with an arrow from the monster soul pointing to a human soul. The theory was that, in between the Amalgamates waking up and when they melted, Alphys had plans to use DT to make Mettaton's soul tough, like a humans'. But then the amalgamates melted. When Frisk's soul resonated with Mettaton, as well as copying whatever let it use magic, it gave Mettaton's soul a tiny, tiny dose of DT-enough for the things Alphys had put in to allow for the tough soul thing to happen, not enough for the negative side-effects. The theory also said that that's why Frisk's soul starts as upside-down in those fights-either Frisk can very, very quickly switch it with their phone now that the upside-down state is stable with its slight alterations, or Frisk can flip it at will. That's now my headcanon, with the added bit that magic-using humans need to flip their soul, which is very hard normally and, usually, if that becomes a stable state, flipping it back is just as hard. So Alphys's thing not only made Frisk's soul able to flip very easily (with a stabilizing coating of Alphys magic at first, which showed Frisk how to magic nerf dart and would wear off slowly as they got used to using magic) but also let them flip it easily at will and let Mettaton flip his soul at will as well-without losing his magic abilities in the point-down configuration. I have some other magic headcanons, including that using DT in magic, while allowing for ridiculous things if you can keep it up (like the Barrier), is generally like using afterburners on a plane: it can't be used for more than about ten minutes. Fifteen minutes if you've got a lot of it. EDIT: added a full stop
Spoiler it's my personal headcanon that mad dummy is hilariously awful at magic so they bully weaker monsters into doing most of their work for them. i mean, they can only shoot a single knife in a straight line and do nothing else on their own, .
Spoiler I think that Mad Dummy just summons the knives, throws them, and then...doesn't reabsorb the magic. And they can only have a few knives manifested at once, and always lose their knives. So they run out of knives, since it takes a long time for the knives to vanish and they haven't figured out that they can just 'kill' the lingering knives. They're like a video game player that has a limited number of items or whatever allowed on the ground, and rather than just picking things back up they wait for them to despawn.
DANG IT I had this nice long response typed up and the site reset deleted most of it! >:( Spoiler The point about monster vs human souls and the like... polarity of them? And how Mettaton's seems to have been enforced in ways that puts it upright like a human's, able to temporarily emerge and be targeted like ours presumably does. Those are interesting. Alphys gives us the ability to shoot whatever it is with our phone when she has us press the button that flips our heart around, though it doesn't seem to be magic magic; Mettaton's box form, invulnerable to physical attacks, is invulnerable to the pew pew. The main reason I hesitate to headcanon the idea that Mettaton's magic is connected to our human coming through is that Mettaton doesn't seem surprised at his abilities. He seems confident and familiar with them like he'd had them them long before the human came by. ...But. Either Alphys and Mettaton are the worst tacticians/strategists ever, or there's something to this. In a pacifist or neutral run, we fight box!Mettaton briefly, and he's completely vulnerable to our attacks (a particularly durable metal body, with no exposed soul). In a nearly complete geno run, we 'fight' Mettaton NEO, a one-hit kill who seems to have no attacks (you can check him over and over, he does nothing). Box Mettaton (or Mad Dummy) could have stalemated us more efficiently than Sans, being invulnerable to our attacks. But he swapped to the NEO form, which seems to be all flash and no substance, instead of the EX form which has some abilities, or sticking to the box form. So maybe there is something about a resonance.
Spoiler Monsters are made of magic and seem to have instincts about it-resonanced!Mettaton probably instinctively knew how to use his new abilities, and they were probably on the specs Alphys gave him anyway. Also, he's an actor. Even if he wasn't feeling confident, he's probably good at pretending to be confident. (And if he's using some of Alphys's magic, he's also probably used to using magic copied off other people...not that his magic is anything like what I headcanon Frisk's magic to be like.) I hadn't thought about Mettaton only being invulnerable when resonanced, because I haven't played the kill-all run, and so I tend to forget that it's a thing. Pacifist runs only for me.
Incidentally Spoiler: Frisk magic headcanons, including spoilers and a somewhat bizarre comparison You could consider Frisk's resonating thing with the Lost Souls to be them having learnt how to do whatever their phone did to set up resonance, but then stopping before anything transferred. You could also consider their buffs and gaining health items in the fight, plus 'but it refused', to be magic. These all have one thing in common. Frisk does them all via determination. So. Frisk appears to use DT-magic all the time, instead of only sparingly when they need a boost. They're easily injured or even killed by normal magic (20 HP, and their soul just breaks apart instead of remaining intact), but just won't die when faced with something completely ridiculous like a point-blank extended shot from an actual god to the face. So. Fragile in normal conditions, toughens in conditions that would kill everyone else. Appears to require DT-magic to do anything at all-the only time they use non-boosted magic is when someone else is supplying it. Uses something that would melt everyone else as their standard magic fuel. Frisk's soul/magic can be compared to the SR-71 Blackbird spyplane. Which, incidentally, used less fuel the faster it flew. So...Frisk is probably that one weird mage who can't do low power spells at all, DT-boosts 100% of the time unless someone's offering to provide the magic for them, tends to make most spells explode from excessive power input if not focusing on keeping their output low (and sometimes even then, if they decide to do something like change spells fast), can take up to five minutes to switch spells, and tries to have every spell use as close to their soul's safe upper limit as possible because "it's less tiring that way".
That entire weird headcanon thing actually all spirally off from the 'DT-magic is equivalent to afterburner" thing. It also got the song version of a nursery rhyme stuck in my head, so.
Spoiler considering everything people have come up with in the discussion so far, i figure that the pew pew alphys gives frisk is intended to be simple magic that does 0 magic damage, rendering it useless against more physical entities like mettaton's box form, while being absorbed by magical entities such as mettaton's EX form. the reason why the EX form starts losing arms and legs without taking any damage is because it cannot handle the amount of DT frisk is shooting into him along with the safety-magic. at a high LV, frisk is probably boosted enough to render the box form's 999/255 DF moot, which is why he tells them that he'd really rather not battle them. at this point, mettaton has no way to survive even a weak hit from frisk, so he uses the NEO form as a gambit to stall for precious time by being flashy so alphys can have a chance to evacuate hotlands and new home (minus asgore, who presumably refuses to evacuate thinking the player can be reasoned with after being informed by flowey of their arrival.
Spoiler also the whole resonating with mettaton's soul thing is pretty interesting when you consider how the player was originally intended to marry him
Spoiler: Mettaton battle spoilers Mettaton's limbs will fall off even if you miss every shot or don't shoot at all. He literally dances/poses so hard his limbs come off.