This is my first fic, so don't judge too hard.
"SANS!"
Sans woke up with a small jolt. His brother's voice was loud, but he wasn't used to being woken up like this. Normally, he just woke up on his own schedule. Then again, he was also used to being woken up by Frisk when they came over, and sometimes Undyne if she came over and had fallen asleep on the couch...
"ENOUGH BOONDOGGLING, SANS," shouted Papyrus, interrupting his train of thought, "I NEED YOU DOWNSTAIRS!"
Sans sighed and quite literally rolled out of bed, landing on the floor with an audible thunk. He got up, put on his signature jacket and slippers, and walked downstairs.
"SANS! THERE YOU ARE! I NEED YOU TO DO ME A FAVOR." Papyrus was pacing the kitchen so rapidly that Sans thought he might bore a hole into the floor. "I NEED YOU TO GO TO THE STORE AND PICK UP SOME THINGS. SPECIFICALLY SPAGHETTI. THAT IS VERY IMPORTANT."
"why don't you do it yourself, paps?" Sans replied, tired (as per usual).
"I WOULD, BUT I HAVE A VERY BUSY SCHEDULE! I HAVE TO RECALIBRATE THE PUZZLES, MEET WITH UNDYNE, PATROL MY STATION..."
"wow. sounds like you have a lot to ketchup on,"' Sans punned. He watched a furious look dawn on Papyrus' face, knowing that he would yell at Sans in 3, 2, 1…
"SANS! YOU ARE NOT HELPING! JUST TAKE THE LIST AND GO," Papyrus shoved the grocery list into his brother's hands and ran out of the house to recalibrate the puzzles before the day ended.
"welp, time to go grocery shopping," muttered Sans, scanning the list. Right off the bat, he spotted ketchup on the list (he didn't even realize they were out), and after looking further, some others like spaghetti (of course), tomatoes, and chisps, none of them sticking out to him. In fact, he didn't see anything on the list as particularly important. He wondered why his brother had sent him to the store in the first place...
*time skip*
Papyrus returned to the house a few hours later, happy that he had managed to finish everything in such a short time span. His brother was sitting on the couch, watching TV, a bottle of ketchup in hand. "sup, bro?"
"SANS! HELLO!" Papyrus was happy to see his brother, but it slowly dawned on him that he didn't see any groceries. "WHERE ARE THE GROCERIES, DEAR BROTHER?"
"they didn't seem important."
"ARE YOU SAYING THAT YOU DIDN'T GET ANYTHING ON MY LIST?!"
"well, i did get ketchup." Papyrus sighed.
"IF YOU AREN'T GOING TO PICK UP GROCERIES, I WILL!" Papyrus stormed out of the house and walked toward the nearby shop, wondering what in the Underground he was ever going to do with his lazy brother.
What did you think? Feel free to give me requests and prompts in the reviews. I will do more as inspiration hits!