Sans wasn't excited about Ink's gift. Maybe he will entrust him with something dangerous that could end human and monster life. Ink reached into his bag and pulled out a cyan vial. He handed it to Sans but he did not took it. "What is it?" Sans asked. "Your gift silly" Ink said, still with a smile. Sans examined it then Ink. He noticed that he wasn't wearing his slash or any of his vials.
"Is it dangerous?" Sans asked. "Nope" Ink replied. Sans sighed and accepted it. Ink stood up and said "sorry I couldn't stay for the party. I've got more work to do". "Are you sure you can't stay Mr. Ink?" Asriel asked. Ink rubbed his furry head and replied "sorry Asriel. I'll come by next time". Ink opened a portal and waved goodbye. Ink exited the AU and jumped to the next.
Sans looked at the vial with insecurity. Something feels off. The vial's color is familiar- too familiar. Sans kept it in his pocket and joined the party.
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Error entered Underswap. The cheery atmosphere made him feel… relieved. He took a breath and let it out. "I'm finally going to see her again" Error thought. He looked over the peaceful horizon and went to find Blueberry and Stretch.
He went to a park and saw the monsters and Chara having a picnic. He doesn't know if they'll forgive him. He went up to them and greeted "hey. Remember me?". Stretch was alerted and throw on some bones at him. Error pulled the bones down with his strings. "Now we don't need to be stretchy in a beautiful day" Error said and chuckled at his own joke.
"Why are you here?!" Stretch asked, more in anger and range than confusion. Error sighed and said showed a light orange vial in his palm. "This is yours" Error said. The monsters were all confused. They all remember what happened in a form of a dream and expected Error to be the bad guy, but he looks so innocent right now. What does Error truly want?