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The resets had never hurt you before. Never. You could always do what you wanted, kill them and then spare that, destroy things and repair them flawlessly, and then reset so you could see what would happen if you did things differently. Sure, there was the deja vu some characters had from past timelines and, sometimes, a character would become aware, but it was never a big problem. Usually, you could fix that and return the character to normal, while others just had to deal with it. You were just trying to get the perfect ending, so once you do it wont matter anyway, they'll be thankful. But, like you said at first, resetting had never failed you this bad.
Where... where are you? You look around, dazed, confused, frightened. This isn't the Underground, you know this from the fact that you can see the sky so clearly. This certainly isn't Mount Ebott, either, judging by the distinct lack of a mountain. When you reset, you always go back to the exact moment where you're falling through the mountain and towards your new adventure, so why aren't you there? Why is it that you seemed to be nearly shaking with hunger and exhaustion. Why... why are you an animal, with light brown fur covering your entire body? What went wrong through space and time to make you into this, was this even your dimension? It couldn't be. Why... now of all times, of all resets? You were so close to saving everyone and getting a perfect ending, but saving Asgore always proved to be a challenge.
You slowly stand, and immediately notice how weak and vulnerable and... small you feel. You're open to any attack and are much too weak and afraid to act in any way that could possibly save your life in that moment. With every step, you limp, and a small, strained whimper leaves your lips. You're shaking, more and more ready to fall down and starve the longer you walk. It would be easier, to give up. Whatever happened with the reset, it left you feeling weak, useless and hurt, like you'd been fighting the odds for days, maybe weeks. But, something inside you doesn't allow you to just drop and take the easy way out. You have determination. Determination that you'll find people, get better, travel back to your dimension and find the perfect ending. That's all you want.
You reach the edge of of the forest you've been trekking through and decide it's best to sit and catch your breath. You think about what you've done and what you'll do next. Perhaps, if you sit here, somebody will come, find you, and give you mercy. You try and breathe, but your nerves seem to be tight and constricting.