Something is rotten in the state of... Everchange.
Well, perhaps not rotten, but certainly wrong. At least, that's what some odd ponies seem to think; doctors are calling this strange new disorder some form of magical group hallucination, but they can't quite pinpoint what's causing it or where it came from. In truth, there's not even any signs of magic on the sufferers, though there's also no sign of other illness - no virus, no bacteria, no fungus writhing in the depths of their brain... Ostensibly, it's agreed on that there's nothing notably wrong with the sufferers, yet their thoughts are obviously unsettled!
Unless you ask the sufferers themselves, of course - the whole issue itself. Each and every one thinks it's not them that's ill, but the world. Outlandish claims bubble up from those suffering from the "New Year's Delusion": things like certain ponies looking alien and strange (when they obviously are not!), certain breeds not existing (when clearly they do!), and entire passages of history being incorrect or false.
Medical and magical professionals alike are uncertain how to handle this new development, though they're hard at work trying to find a cure for those poor souls. Of course, it's truly unknown how many have been afflicted by the disease; while there are some that have completely snapped, leading to the wider publication of the affliction, many suspect there may be countless others simply keeping their silence on the matter. It wouldn't be surprising, experts say - after all, how would any sane person react to waking up to what they believe is an entirely changed world?
One thing is certain though: everyone hopes this strange madness will come to an end quickly and its tarnish can be removed from an otherwise brilliant start to another new year. It's such a terrible condition to think about...
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On the flip side of the coin are the sufferers - the ones who know the truth. These ponies aren't sick, they'll tell you, apart from perhaps living in shock or horror at the world they see around them. No, they're not sick, they just remember. They remember the Sphere, that wretched thing they speak of in hushed tones; they remember the world as it was, and they can still see the fragments of what used to be.
They know those strangers didn't exist; no noolah ever first bounced down the mountainside to greet the rest of the world, and no slimes ever bubbled up from the rocks to greet their neighbors. They know that mers are mers and aquatics are aquatics and all this polpo and seabell and reefhopper and lakeskimmer nonsense is garbage! They know that ryujin are lungs, and they're just wingless dragons.
More than that, they recognize the strangers. They can see the differences that others, somehow, for whatever reason, can't. They see those ponies-that-aren't, the ones who look different, whose legs and bodies and heads and ears and everything therein are just different. Not so different they could be called aliens, but different enough to not be the same - something that most, apparently, can't see. Even when the differences are pointed out to them directly, they just shake their heads and laugh it off. How can they not see? How can they not understand that they are being erased?
The "New Year's Delusion" isn't a delusion at all - it is a glitch, a spark of something that shouldn't have been. When the Resolution Sphere broke, the world changed, and most changed with it. Memories and experiences warped to fit this new reality which, ostensibly, is reality now. Yet with any great change comes... bugs. In this case, it's ponies who, for lack of a better term, didn't get rewritten properly. Bits and pieces - memories - of what used to be still exist, even though those realities are no longer real.
It's not very common; while it's certainly made the news, it is actually quite rare, though not as rare as people think. Most aren't driven to insanity from it - it's simply a part of their lives now, however strange or terrifying it might be. Some are drawn to seclusion from it, others seem to be embracing this chance at a new existence.
And you? Well, perhaps one of your ponies is afflicted with this strange memory of what no-longer-is. This is the place you can try and find out.