3. Underswap

"HIYA!"

"Oh, Sans. What are you doing here?"

"WORKING! HAVEN'T YOU SEEN A GUY WITH TWO JOBS BEFORE? TWICE AS MANY JOBS MEANS TWICE AS MANY PROMOTIONS, SO I'LL BE A ROYAL GUARD IN NO TIME!" He bounced up and down behind the sentry station, and Chara smiled.

"Of course you will. You always get what you want, don't you?"

"Y'KNOW, IT'S BEEN A COUPLE DAYS SINCE I TOOK A BREAK. Y'WANNA HEAD DOWN TO SNOWDIN AND GRAB A BITE TO EAT WITH ME? IT'S ALWAYS IMPORTANT TO KEEP YOUR STRENGTH UP!"

"Fine. I think I went everywhere in Snowdin, but I can't be positive."

"WELL, YOU'RE IN FOR SOME OF THE BEST FOOD EVER! COME ON, I KNOW A SHORTCUT."

He climbed out from behind the booth, and ran in the opposite direction of town. Chara hesitated, then ran after him.

The world went black for a second, almost as if they had passed out. They blinked, and suddenly...

"FAST SHORTCUT, HUH?"

Chara squinted, trying to adjust their eyes to the light. It looked like a fairly nice restaurant - wooden walls, cozy booths. But it was empty. No patrons were sitting around, eating or talking or playing cards. There was only a barkeeper, scrubbing a table in the eerie silence.

"Son!"

The barkeeper, a gangly creature in a dapper vest and bowtie, rushed towards them, crossing the restaurant in three steps and scooping up Sans in a bone-crushing hug.

"HI, DAD!" Sans squeezed the figure back.

"Dad?" muttered Chara.

Sans pulled back and motioned at Chara.

"YEP! HUMAN, MEET MY DAD, W.D. GASTER. DAD, THIS IS THE HUMAN."

"Hiya! It's really great to meet you! Pappy mentioned you when he came in earlier, and we've all heard the stories." He grinned. He was definitely a skeleton, if a little... different. His eyes glowed like Sans, but brighter - almost like flashlights. One orange, one blue. There was a wide, perfect circle cut out of each of his palms, and two odd scars arched from his eyes up and down his skull. He stared at the human with an odd look in his eyes.

"I'm glad you're safe. I haven't seen many people today, which is funny! Usually they're all over, coming in, going out, all that jazz!" He shrugged, laughing. "Maybe today they're all actually doing their jobs!"

MAYBE! FOR BEING SUCH GOOD FOOD, NOT MANY PEOPLE KNOW ABOUT THIS PLACE. IT'S PRETTY UNDERGROUND." He winked. "LET'S EAT! WHATDAYA WANT?"

"Hamburger or fries? On the house, of course." Gaster ran back and jumped behind the bar.

"I don't want anything."

"C'MON!"

They rolled their eyes. "Hamburger."

"GREAT CHOICE! DAD, A DOUBLE ORDER OF THE BURG, PLEASE!"

"Comin' right up!" Gaster stepped back into the kitchen.

Sans leaned over the bar and grabbed a bottle of mustard from the condiments rack.

"HEY, WHILE WE'RE WAITING, I WAS JUST WONDERIN'. YOU'RE HEADED TO HOTLAND, RIGHT? TO THE CAPITAL?"

Chara shifted in their seat. "Uh… yeah?"

"YOU EVER HEARD OF DR. GRILLBY?" He stared at them with bright, curious eyes, his head tilted slightly to the right.

"Who now?"

"IT'S SORT OF A LEGEND. YEARS AND YEARS AGO, DR. GRILLBY,THE ROYAL SCIENTIST, FELL INTO THE CORE AND DIED. HE WAS A FIRE ELEMENTAL, AND HIS SPIRIT WAS SCATTERED THROUGH HOTLAND. HE'S A GUARDIAN, A PROTECTOR! THAT'S WHY IT'S SO HOT!"

Chara raised an eyebrow. "Isn't it hot because it's the middle of a volcano?"

"YEAH, WELL..." He shrugged. "HE WAS A REAL PERSON. DAD KNEW HIM WHEN HE WAS ALIVE. DON'T KNOW HOW MUCH OF THE REST OF THE STORY'S TRUE."

Gaster kicked the kitchen door open, and tossed two loaded plates down on the bar.

"Ta-da!" he sang. "Bone appetite!"

"REAL FUNNY, DAD," sighed Sans, dumping the bottle of mustard on his burger. Chara ignored the food, staring at the skeletons.

"Have you heard from Papyrus recently? I mean, he was in here this morning, but I haven't seen him since. He's not answering his phone."

"NAH, I HAVEN'T. HE'S PROBABLY OFF SLEEPING SOMEWHERE." Sans' eyes narrowed, and he crammed the burger into his mouth. "OKIE-DOKE! I BETTER HEAD BACK TO WORK. SEE YA, DAD!"

"Goodbye." Gaster watched as the two left the empty restaurant, an odd expression crossing his face. "Stay safe..."

Then, they were back at the entrance of Waterfall. Sans climbed behind his booth and held out a hand.

"WELL, THAT WAS FUN! WE OUGHTA-"

Then, they were grabbing their knife. They were diving across the booth, swinging wildly. They were staring down at Sans, who was clutching his chest.

Yellow goop was oozing out a hole in his armor, as if he had hidden a bottle of mustard in his ribcage. He stared up at them, an odd look in his eyes.

"IT WAS YOU, WASN'T IT? YOU'RE THE REASON WHY EVERYONE'S GONE. YOU... YOU KILLED..." He sat down, watching as the stains spread over his scarf. "THAT MEANS PAP... PAP..."

A sudden bone flew out of the air, smashing into the side of Chara's skull. They blinked, but it only took 4 off of their substantial HP.

"Your brother is dead," they said. Sans' eyes flickered shut.

"NO... NOT..." He glared up at them. "KIDS LIKE YOU... KIDS LIKE YOU SHOULD BE..."

Chara turned away, wiping the dust off their face. That was easier than they had expected. His older brother had definitely suspected something, and had put up a fight. Who knew that the brat only had 1 HP?

They stuck their knife back in their belt and began pushing through the reeds.

Then, they were out of the marsh. It was a long hallway, made of the same, bluish stone. There was something oddly familiar about it, even though they were sure they had never been there before. They pulled their knife back out.

"So."

They spun around, gripping their weapon as a cloaked figure stepped out of the shadows. Its hood was pulled low, but they could still see its eyes glowing. One blue, one gold. Like flashlights.

"Gaster," snapped Chara. The skeleton pushed its hood back. He was grinning, but it was empty of emotion. His smile was dead, just like theirs.

"So you think it's funny to hurt those around you?"

Two spirits appeared behind him. Skeletons. One blue, one gold. Then something different - flickering, uncertain. The room became much warmer.

"Then you're going to find this hilarious."

A/N: Golly. This was my first time writing a genocide run. I know, traditionally Gaster and the Riverperson are swapped, but I'm kinda in love with the idea of Gaster being a goofy, gentle barkeeper and Grillby being a salty Hotland spirit. Got an idea? Leave a review or a PM, and I might make it into a story! Anyways, I do not get credit for this, Underswap belongs to Popcorn Pr1nce, and Undertale belongs to my boy Toby.