Notes:
Frisk and Chara are both female.
The location and setting is based on the Ask Frisk And Friends comic series.
Basically, Toriel, Sans, Papyrus, Asgore, Undyne, Alphys, Flowey, and Frisk live in a house together on the surface.
And yes, I know Frisk is called "They" in the game, but since I have given her a gender I will refer to her as "her"
It was a nice afternoon for Frisk, considering she was hanging out with Sans and Papyrus. They had just finished eating lunch.
"Anyone up for 5ths?" Papyrus asked, spooning more spaghetti on his plate.
"I'm stuffed, Pap," Sans said, wiping his mouth on his sleeve. "That spaghetti was saucesome." Papyrus chuckled at Sans's pun and began to eat his spaghetti. Just then, Sans's smile got even bigger and he turned to Frisk. "Hey kiddo, you wanna help me prank someone?" He asked her.
"You really mean it this time, or are you just messing with me?" Frisk asked, giving a small scowl.
"No, it won't be like last time," the skeleton replied, picking Frisk up and placing her on his shoulders. "Come on, let's go prank Alphys." The two began to ascend the stairs to the basement, where Alphys mainly worked on experiments, or watched anime. But now she was upstairs working with Undyne. Sans walked into the lab where many different experiments lay unfinished or broken. Some were mechanical, some were different mixes of liquids in test tubes, and others were just taken apart.
"So how are we going to prank her?" Frisk asked.
"We mess with her experiments!" Sans replied, setting Frisk back on the ground. He reached into his pocket, and pulled out a small fire rocket. He handed it to Frisk. "Tie this around anything you'd like, but don't tell Tori," he said, holding a finger to his teeth.
Frisk smiled, "My lips are sealed," she said, taking the rocket. She noticed that the rocket had some kind of antenna connected to the fuse. She tied the rocket to a robotic arm and ran back to Sans.
"Here, take this remote, when Alphys comes down press the button," Sans said, handing her a small remote with an antenna. They both hid behind a shelf of various liquids in bottles, some were even on top of the shelf. They stood and waited. Eventually, Alphys came down the stairs and grabbed the TV remote, she was about the turn the TV when Frisk pressed the button. The robot arm flew off the ground and around the room! Alphys jumped at this and ducked as the arm flew past her head. She scampered about the room, trying to avoid being hit. The arm flew into walls and shelves, knocking things over and breaking them. Sans and Frisk were watching the whole thing, trying their best not to laugh. Then the rocket ricocheted off the wall, and flew straight into the shelf that they were hiding behind. The shelf swayed, causing bottles to fall from it. One of the bottles on top of the shelf tipped over, it tumbled down and landed on Frisk.