Hypothermia
The cold hit Frisk like a wave as soon as they got the door open. They stepped through slowly, looking around to realize that they were now in a giant, snowy forest.
Before they could have second thoughts about moving forward, the door behind them closet shut and clicked with an air of finality. Fear sank into the pit of their stomach, making them feel colder than the weather. They realized that for the first time since they met Toriel, they could truly be in danger, and no one would come to rescue them.
They walked forward slowly, quickly growing colder and colder as they swiveled their head to monitor their surroundings. They put their hands in their pockets to try to keep their fingers warm but to no avail.
A noise echoed through the silent forest, and Frisk broke into a run.
They came across a large stick, but it was too big for them to pick it up, so they jumped over it and kept running. The stick suddenly snapped behind them, and they looked back in fear to find that no one was there.
They ran faster.
They stopped to catch their breath at the first bridge, and as soon as they put their hands on their knees, they felt a presence behind them. They gasped and shot up straight as whatever was behind them spoke. How did it even get there? Were all monsters this fast?
They followed the monster's instructions and turned around slowly, raising a numbed hand to shake the clawed hand in front of them.
It turned out to be a fart joke, and, wow. This wasn't so bad.
Except that they couldn't feel their fingers anymore, and they were pretty sure that their nose had fallen off their face.
It was too cold.
Hiding behind the lamp might have obscured vision, but it did nothing to stop the howling wind, and it took all they had not to topple the lamp over with their shivering. Then they had to do puzzles in the freezing cold, and it was a good thing puzzles weren't so hard, as most of Frisk's concentration was on how to keep themselves warm.
More than once, they almost stopped to ask one of the skeletons for a piece of clothing, but Frisk was playing their game, and they feared that any disobedience would end their life.
Not that it would last much longer.
They stumbled to a cave with strange mushrooms and a locked door and took refuge form the bone chilling wind. It felt better, but they quickly realized that there was no way to get warm in there. So, with determination and a little bit of fear, they stumbled back outside into the snow.
By the time Frisk got to the bridge, they could barely walk from the cold. The sound of the snow crunching under their feet was muffled, and their vision was growing dark around the edges. Their eyes fixated on the flamethrower trap for a few moments before their knees gave out, and the world went black.
"I KILLED THE HUMAN, SANS!"
"Nah. It's still breathing."
…
"I AM THE WORST MONSTER TO EVER EXIST! I KILLED THE HUMAN!"
"Just run faster, bro!"
…
"WILL THEY BE ALRIGHT?"
"I don't know."
"I HOPE SO."
"Me too, bro. Me too."
Warmth.
Frisk opened their eyes to the orange glow of a hearth fire, and, for the first time since leaving the ruins, they could feel their fingers.
They found themselves swaddled with a heap of blankets and jackets, with more than one scarf wrapped around their neck and head. They felt so warm and toasty that they didn't want to move, and decided that sleep was a better option. So they slept.
The next time they woke up, they found the taller skeleton—Papyrus, their hazy mind supplied—adding an extra blanket to the heap that was already piled on top of them. The skeleton blinked in surprise at their open eyes before looking happy and relieved.
"HUMAN!" Frisk winced; he was loud up close. "YOU'RE FINALLY AWAKE!"
Frisk nodded.
"SANS! THE HUMAN IS AWAKE!" He called out into the large house, "HOW ARE YOU FEELING, HUMAN?"
"Warm," Frisk answered, and then their stomach growled. "Hungry."
"OF COURSE! I, THE GREAT PAPYRUS, WILL MAKE YOU SOME OF MY SPAGHETTI!" He got up, the blankets in his hands completely forgotten as he rushed out of the room. He came back to their side immediately, placing the blanket on top of the pile.
"DO NOT MOVE, HUMAN," He ordered before leaving again.
Frisk couldn't move if they wanted, even though it was getting too warm under the pile. A bolt of panic ran through them as they remembered that they were being hunted in the Underground, and that they were very likely Papyrus' prisoner.
Escape. They needed to escape.
Frisk wiggled their fingers and toes, and was relived to find that they still had control over them. Next, they tried moving their legs, but there were too many blankets and jackets in the way. Their arms were just as hopeless, but their shoulders held a much lighter load on them, and they moved more freely.
So they started violently wiggling their shoulders and head left and right in an effort to free themselves. A breathless chuckle sounded beside them, and they froze in a panic, not wanting to get caught before they could even make their escape.
"Here, let me help you." The shorter skeleton—Sans was his name—came into view, and started to remove the blankets and jackets off of Frisk. They waited until enough blankets were off before raising their arms with as much power as they could muster. This resulted in their arms exploding out of the pile, scattering a few scarves and blankets everywhere.
Sans didn't even flinch, but snickered at the colorful gloves that adorned Frisk's hands.
Papyrus chose that moment to come in with a steaming plate of spaghetti, and Frisk's stomach rumbled loudly in reaction to the sight.
"HUMAN, I'VE BROUGHT YOU FOOD," the tall skeleton declared proudly, "AH, I SEE SANS GOT YOUR ARMS FREE ALREADY! THANK YOU, SANS."
"Sure, bro."
Papyrus set the plate of spaghetti on top of the pile in front of Frisk and handed them a fork and spoon. They instantly dug in; the taste of the meal was subpar, but they were way too hungry to care.
"More please," Frisk said once they finished the plate. Papyrus looked ecstatic, and took the plate back to the kitchen with the flair of an action hero. Sans gave Frisk a warm smile before heading upstairs, and Papyrus came back with a new plate of spaghetti before Frisk had time to wonder where Sans was going.
After the second plate of spaghetti was eaten, Frisk leaned back in their pile of warm fabrics and closed their eyes, feeling very sleepy. Papyrus took the plate from them as they fell asleep, feeling safer in the company of the skeletons.
They awoke a while later, feeling way too warm and uncomfortable. They had been covered with another blanket, as to keep their free arms warm, and, while they appreciated the sentiment, it still set them on edge. So they kept removing layers of blankets and jackets until they were comfortable. Once satisfied, they looked around and noticed that there was no one in the room with them, and now that their arms were free, they could escape their captors.
Yet, it was still too cold outside, and the skeletons were really nice. It didn't really feel like they were prisoners here at all.
Papyrus had come back to check on them before they could make up their mind. He seemed delighted to find them awake.
"HUMAN!" He said happily, "HOW ARE YOU FEELING?"
"Good."
"EXCELLENT," he rubbed his hands together, "WOULD YOU LIKE TO TRY AND STAND UP?"
"No," Frisk shook their head, "too cold."
"HMMMM. THAT WOULD BE A PROBLEM FOR YOU, WOULDN'T IT?" His hands came up to rub his head before he snapped his fingers, "AHA! I, THE GREAT PAPYRUS, HAVE JUST THE THING!"
Papyrus ran up the stairs, and Frisk heard pounding knocks and some yelling before everything went quiet for a while. Then there was more thumping as he ran back downstairs and appeared at Frisk's side.
"HERE YOU ARE," he said happily, tossing Frisk a big, wooly, purple and blue sweater, "I MADE IT MYSELF! FOR I, THE GREAT PAPYRUS, AM GIFTED WITH MANY TALENTS, AND MAKING WARM AND WOOLY SWEATERS IS ONE OF THEM!"
Frisk looked at the sweater and hesitated for a moment before shrugging and putting it on. They were pleasantly surprised at how comfortable the sweater was, but it was way too big on them, with the sleeves hanging well beyond their hands. They looked at Papyrus for his opinion, and the skeleton looked mighty pleased.
"EXCELLENT! NOW, GET UP AND GET MOVING!"
Well. He asked for it.
Frisk stood up very quickly, and all but burst from the pile of warm fabrics. They braced themselves for the cold, but found themselves to still be surprisingly warm. Papyrus then handed them a hat and a scarf, which matched with the gloves that Frisk was already wearing. They put them on and looked at the skeleton for his approval, and he looked at them expectedly.
Frisk took a look around before taking a few steps to see how steady their footing was. The first step was shaky, but the rest were pretty steady. They stood still for a few seconds, trying to figure out what to do next. Running was the obvious choice, but in which direction? Could they get to the door before they get caught? They figured that they could, but it would hurt their host's feelings, and they didn't really want to do that.
So they ran into the house instead. They dodged around the tall skeleton and ran up the stairs, giggling as chased after them.
They got to the end of the hallway before they were caught. Gloved hands grabbed them from their waist, hoisting them up into the air.
"I CAUGHT YOU!" Papyrus cackled, and Frisk laughed, "AND NOW, YOU CATCH ME!"
He put them down and took off running, and they ran after him. They lost their footing as they chased him down the stairs. They braced for a nasty fall, only to be caught by Papyrus. The skeleton held them firmly and placed them gently on the ground.
"ARE YOU ALRIGHT, HUMAN?"
Frisk nodded.
"YOU SHOULDN'T RUN DOWN THE STAIRS, HUMAN. THEY'RE DANGEROUS! YOU'RE LUCKY THAT I, THE GREAT PAPYRUS, WAS THERE TO CATCH YOU!"
"Thank you," Frisk said.
"YOU'RE WELCOME!"
Frisk then hugged Papyrus, flustering him. He looked down at the human, and they looked back at him with a devilish grin.
"I caught you!" They snickered before taking off into the house, with Papyrus chasing after them. If this was how it was outside of the Ruins, they thought as Papyrus caught them again, then maybe everything would turn out better than what they've been told.
And that thought filled them with determination.