Mangled22 on Deviantart asked for this one. Here you go, Amiga! Enjoy! :)

Undertale belongs to Toby Fox. Underswap!Sans (Blue) belongs to Popcorn Pr1nce on Tumbler. Error belongs to TheCrayonQueen on Deviantart. I own nothing.

A Rare, Happy Feeling

Blue was happy as he skipped down the path to his home. He and Chara had just finished some puzzles and he was pleased that she was getting better at solving his puzzles. He was deciding on how to create more puzzles for her when something grabbed him from behind and he gasped, but was pulled backwards into a glowing white light, which closed soon afterwards.

Blue glanced around, wondering where he was when he turned and found a very odd skeleton in front of him. The skeleton was black with red eyes, clothing that was red, black, and yellow, and blue lines ran down his face from his eyes. A word kept glitching around him and it took a moment for the bubbly skeleton to realize what the word was. "Error?" He said softly, wondering why that word was glitching all over this skeleton.

"Y-You're now m-my pr-prisoner," the skeleton said to him in a voice that was scratchy and sounded a bit like static.

Blue cocked his head to the side. The skeleton was speaking similar to how Undyne stuttered when she spoke, but this sounded like more than just stuttering. It sounded like glitching and he looked at the skeleton in sympathy. "Are you injured?" He asked kindly. "I can help you recover."

Error looked at him with surprise before snarling. "No!" He yelled. "I'm not in-injured! And stop st-staring! Yo-You're my prisoner!"

Blue felt even more sympathy for the skeleton in front of him, who looked to be trying to hold himself together as he glitched badly. "Please, just let me help," he said. "I can make you some tacos. I love cooking."

Error let out a cry of anger before throwing some blue strings at Blue, who dodged them expertly, looking concerned. "I'm not looking for a fight," he said gently.

That took the cake for the glitching skeleton and he let out a frustrated groan before sitting down in a heap on the ground, looking away from Blue, who cautiously moved closer, wondering if the skeleton was alright. "Are you alright?" He asked, his voice still kind. "What is your name?"

It took a moment for the glitching to stop and the skeleton looked up at him in surprise. "Wh-Why do you w-want to kn-know my n-name?" He asked.

Blue smiled. "Well, isn't that the first thing about making friends?" He asked. "At least, that's what Chara taught me."

The dark skeleton's shoulders slumped at seeing he couldn't strike fear into the skeleton beside him. "Error," he said.

Blue looked at him. "Error? That's an interesting name," he said honestly, though inwardly he did find it unusual, but he didn't want to hurt his new friend's feelings. "I'm Sans, but you can call me Blue."

"I know," Error said, looking at him. "I know all about you. Your AU is Underswap and you're training for the Elite Guard."

"Yes," the bubbly skeleton said, beaming. "I'm hoping to be a strong leader someday like Captain Alphys. She's so cool! I've always wanted to be like her ever since I was little."

The dark skeleton sighed as he listened to the skeleton talk excitedly about his dreams and how he wanted to make friends and how Chara was helping him out and how she was a sweet girl. While Blue kept up the steady stream of talking, Error wondered why he couldn't make Blue afraid of him. Most Sanses he captured either cowered before him or immediately put up a fight and escaped, which was why he captured Blue, thinking the bubbly skeleton would be an easier target. But that idea went down the drain.

After a bit, Blue felt his stomach growl. "Oh, that reminds me. Have you had lunch yet?" He asked Error, who barely had time to shake his head before the bubbly skeleton spoke again. "I'll go make us some tacos! Chara's been helping me perfect my recipe and my tacos have been delicious if I do say so myself."

Error was about to speak but then decided against it. Anything he said was just going to either go over Blue's head or he would just say something unexpected. Moments later though, he was actually kind of glad he didn't say anything because the delicious smell coming from his kitchen that he rarely used was actually making him hungry.

Blue came out moments later with a plate of tacos. "Ta-da!" He said with a grin, giving the plate to Error. "Eat up while they're hot."

Since he couldn't strike fear in the bubbly skeleton, the dark skeleton decided to humor his 'guest' and began eating the tacos. To his surprise, they were very tasty and he dug into them ravenously, unable to recall when he even ate anything.

Giggling at his new friend's appetite, Blue went and got him some more tacos, which he dug into just as ravenously. The bubbly skeleton then ate some tacos too, having made more than enough for the two of them. Error ate about four plates of tacos before he leaned back, his stomach full and a smile on his face. For some reason, the tacos made him forget that he had been looking to hurt Blue earlier. He was filled with a content feeling that he hadn't felt in a long time.

Blue smiled as he saw his friend was full and looked happy. "Was it good?" He asked.

Error nodded. "Delicious," he said. "You're good at making tacos."

Another grin lit up the bubbly skeleton's face. "So you'll take me back to my AU?" He asked hopefully.

The dark skeleton shook his head. "No," he said, the smile leaving his face. "You're my prisoner, remember?"

Blue actually looked a bit hurt. "I thought we were friends," he said, poking Error's side. A gasp left the dark skeleton, but it sounded like a surprised gasp and one corner of his mouth twitched. Having caught the odd reaction, the bubbly skeleton gently poked his friend's side again and got the same reaction, only slightly louder. He then grinned and pounced on Error, sitting on his legs. "And one other thing friends do for each other besides making lunch for each other is tickling each other!" He said, his gloved hands going for the dark skeleton's ribs.

A surprised laugh left Error as he tried to squirm, but he was not only full from lunch, but also went into minor tickle paralysis as his ribs, one of his most ticklish spots, were tickled by a now grinning Blue.

"BWAHAHA! STAHP!" He pleaded, wondering how this had happened and why was it happening to him of all skeletons.

Blue giggled. "Take me back to my AU," he said, stars in his eyes as he continued tickling his captor.

"NYEH-EVER!" Error exclaimed through his laughter.

The mischievous skeleton chuckled. "Then I'm going to tickle you silly!" He said, recalling how Chara couldn't stand it when he teased her while tickling her. She admitted that the tickle words and playful teasing made the tickling a lot worse, but didn't mind because she loved it when he made her laugh. It seemed that Error was enjoying it too as he laughed his hardest, pounding the ground with one fist and tears rolling down his face as he squealed again, trying to get Blue off of him.

"AHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA! STAHAHAHAHAHAHAHAP!" He pleaded again.

The bubbly skeleton giggled, giving his captor a breather, but stayed sitting on his legs, not yet through with tickling him. After Error got his breath back, Blue began tickling the dark skeleton's ribs again, making him gasp and squeal loudly before loud laughter filled the room. "Tickle, tickle, tickle! Cootchie, cootchie, coo!" Blue cooed to him before blowing a raspberry into the sensitive ribs.

The loudest squeal left Error's throat as he laughed like crazy now, unable to squirm as he was now frozen with tickle paralysis, unable to do anything but laugh and squeal as Blue continued tickling and blowing raspberries onto the very sensitive ribs.

"AHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA! CAHAHAHAHAHAHAHAAN'T TAHAHAHAHAHAKE IHIHIHIHIHIT!" He managed to laugh out.

Blue smiled, seeing his captor was starting to become tired from the tickle torture. "Take me back to my AU and I'll stop," he bargained. "If you don't, I'm sure my brother can find a way in here and join in and trust me, he is a master at tickle tortures."

Error's eyes widened. If a tickle torture from Blue had him gasping, he could only imagine how out of breath he'd be if Blue's brother came and tickled him. "Okay! Okay!" He gasped out.

Smiling again, Blue kept his word, stopping the tickle torture and helping Error sit up, hugging him as the dark skeleton tried to get his breath back.

Error looked confused, but then slowly returned the hug. He wasn't used to hugs or touching, but something about Blue's hug seemed genuine and it made him...happy, an emotion that was rare for him to feel. He then softly chuckled. "You're brave, Blue," he said. "Not many have tried to befriend me, make me lunch, and then tickle me to pieces."

"Really?" The bubbly skeleton said before becoming excited. "Well, then. I'll just have to come back and make you lunch and tickle you again and invite my brother and Chara along too."

The dark skeleton shook his head with a smile and opened the portal back to the Underswap AU. "There you go," he said.

Blue hugged him again. "I'll see you again, my friend," he said with a smile before disappearing into the portal.

Error smiled a genuine smile at that, deciding that he would make sure nothing damaged the Underswap AU. After all, it wasn't every day that lunch was cooked for him or someone went out of their way to make him feel happy.

It was a rare feeling for him and he wanted to hold onto it forever.

Wow! I had fun with this one. :)

When you guys leave a review, please be gentle. It's my first time writing Error in story, so please, no flames. Thank you.

GoldGuardian2418