Undertale is owned by Toby Fox
Underfresh. [T.H.E V.I.R.U.S]
Backstory: There are many alternative universes in the Multiverse, including a few special ones, like Errortale, Underfresh and Underswap. When Underswap Sans is stuck in the void with all the other Sans, A new mysterious Sans appears, and Swap Sans needs to find a way to save everyone before its too late.
[Please note that this is a first person story and I will be talking in the context of Swap Sans.]
CHAPTER ONE
I hear my footsteps echo throughout the empty void. I can't remember the last time I saw colours, and objects. I can't remember when I saw my brother Papyrus. I sigh. I can't worry about all of this no more, im a prisoner in here for eternity. Im alone but I always here other people screaming, but I can never find them. I wonder why Error would trap me down here, or why won't he let me or anyone else go. Maybe he is just upset, or hurt. I know I could never do this to anyone.
I remember the day when Error took me away from my Universe. It was one peaceful day out in Snowdin, and the Human Frisk arrived. Then I just fell in here, to be faced by him. But oh well. I know I can't escape, I just wish I could say goodbye to my brother Paps, if he is still alive. Suddenly I hear a noise echo through the nothingness, and I immediately run towards the sound because I know who is here. I look forward and I see him. Error signs float around him, his black colour and that unforgettable smile he never seems to wipe of his face.
"Error your back! H-How are you?" I ask him. I hear a small sigh come out of his mouth, and he replies. "H-Ha-Hah-hA H-Hello B-Lue Berry. I-I am O-Kay… JuSt annO-yed over all The-se freak A-U accidents!" I put on a fake smile. I murmur "Oh… Well it should get better soon." He nods his head. "I-I guess.. Your rIght… Anyw-ays I need- to s..ort something out. Don't do anything to an-noy me or I w-ont give yo-u my su-prise." My smile expands on my face, and I shout "A surprise Error? Thank you!". I see him smile and then, he turns into nothing as he teleports away.
Slowly I start walking, thinking what my surprise could be, maybe I would be able to escape! Maybe I-. I suddenly freeze as I hear footstep echoes getting closer and closer towards me. I quickly turn my head, but no one was there. I realise that Error didn't close his portal into a AU. "Oh no…" I whisper. Before I could take a step forward, I hear a voice murmur something behind me. " E." I suddenly stop, and I slowly turn my body round, and I suddenly freeze. "Hey Broski, What's up?" My body doesn't know how to react, so I end up tumbling back and falling onto the floor. He murmurs something else "Broski, don't be scared it's me, your buddy chum pal!" I stop as I see his bright neon colours, and I then notice his shades saying 'Y.O.L.O'.
Before I can get up, he puts his foot on my ribcage, and I can't get up. "Now Broski, Where is that Unfresh Error at? Me and him didn't get to finish our UnRad conversation earlier." He says with a smile on his face. I build up the courage to reply back to him "I-I won't tell you! He is my friend…. Please don't hurt him!" I see him sigh, and then he replies back to me, looking at me with a terrifying stare. "Heh…. That's totally UnRad dude to not tell me… But I guess you're his friend, so If I play around with you, he will surely come by, to save his precious friends." I suddenly loose the smile on my face, as he looks down on me, and he slowly takes his glasses off. Purple ooze drips down from his eyes onto my face.
"H-Hey.. Blu-E beRR y! W-WheRe arE Yo-" I Open my eyes, to see Sanzy away from my face, and looking at Error. The purple ooze makes me weak, and so I just lay there listening to their conversation. Before I can get up, I hear the noise of Gaster blasters surrounding me. I try to call out, but immense pain covers me and all I can here is a loud scream, before everything went black.