Sci POV
I told (Y/N) what to do in this experiment, she was in a testing tube waiting for the experiment to begin. I had a cat in another testing tube, then I began the experiment. After a few clicks, it started I waited for a few minutes then (Y/N) stepped out of her testing tube. I looked at her she had cat ears and a tail that matches her hair color, "Did it work?" she looked so adorable. "I...think so, you're not really a cat though...part cat." she started to feel her new cat parts. "I have ears...and a tail?" I blushed. "From the anime I've seen with Alphys, I think you're called a Neko." she nod. "Cute!" she meowed, then I started to blushed madly. "Oh stars..! That was so adorable!" she grabbed me pulling me into a hug. "Thanks!" she started to rub her face against mine. "What are you doing?" I blushed. "I'm showing you my love!"
(Y/N) POV
Once Sci did that experiment on me, I felt more cheerful than usual I kept rubbing my face against his. "Sorry I got a bit carried away! I'm just too excited!" I giggled. "I-It's fine...I'll be finding a solution for this." he was about to walk away until I grabbed his hand. "No! I wanna stay this for a while...if that's okay...if I need to change back then I'll tell you." he blushed. "You're okay with this?" I nod. "If you're okay with it then I'm okay with it." I smiled. "Thank you!" I hugged him. "So do you need anymore assistance?" he shook his head. "You can stay for a while if you want." I nod, then I followed him into another room. "Oh you're coming with me?" I nod. I watched him as he did some paperwork, I looked around the lab a bit then I surprised hug Sci. "Hi! What are you working on?" he was startled. "(Y/N)?!" I giggled, I pulled a chair sitting next to him. I continued watching him do his paperwork, I understood most of it since I remember my father teaching me some of it.
I then saw him make a mistake in one of his problems, "Sci sorry but I think you made a mistake in one of your problems..." he then realized it. "Oh thanks for catching that for me." he then erased it then put the correct answer. "How did you know all of this?" I giggled. "My father taught me lots of things when I was little." I smiled. "Let me guess your dad's name was Gaster?" I nod. "Hey wanna learn something about the universes?" I nod. "So here's my theory, every choice inside a universe splits it...creating two separate universes. But your choices don't belong to a single universe, they exist directly inside the multiverse." I nod. "I get you." I meowed. "Thanks for listening...usually when I tell those type of theories to the other versions of me, they would fall asleep or ignore me." I looked at him. "Well I'm here to listen to you!" he blushed. "Thanks..." then I remembered something that I've promised to Fresh.
"Oh I almost forgot! I need to visit Fresh!" I snapped my fingers then a portal opened. "Why?" I was about to go inside. "Oh after I told Fresh I was going into your universe, he wanted me to go into his universe." he nod. "Well see ya!" I gave him a peck on the cheek then left into Fresh's universe. It was so colorful mostly 90's theme then I found Fresh's house, I knocked on the door to see Fresh. "Hi Fresh!" I meowed. "(Y/N)..? Why do you have cat ears and a tail?" he blushed. "Oh yeah...that experiment Sci did on me kinda backfired but I'm fine don't worry." I smiled. "Are they real?" I nod. "You're welcome to feel them." I moved down a bit then Fresh petted my head. "You're so cute." he mumbled. "Thank you!" I meowed. Fresh let me inside his house, "Wow your house is very colorful!" he giggled. "Thanks." I flopped down on his comfy couch, he sat next to me then started to pet me. He continued petting me then there was a knock on his door, "Coming!" he got up to opened the door, I stayed put on the couch.
"Glitchy! Hey bruh!" I got closer to see who Fresh was talking to. "What are doin' here?" I saw Error step inside, I sat there looking at Error was a worried expression. "I just wanted to visit-" he saw me. "Well...well...well who do we got here? (Y/N)..? Why do you have cat ears...and a tail?" he stared at me. "It was an experiment from Sci." I replied. "Okay...now tell me why are you in Fresh's universe." I shrug. "Why are you in his universe?" I raised an eyebrow. "I-I wanted to visit him..." he looked away from me. "Now let's continue...how did you escape the antivoid?" then blue strings were about to surround me, thankfully Fresh stopped Error. "Woah bro...can't do that here." Error looks annoyed. "Why?" he looked at Fresh. "Why do you want to capture her?" Error sigh. "She's a threat." Fresh looks confused. "A threat? How?" Fresh crossed his arms. "She...um..." Error didn't know what to say. "See?! You're doing this for no reason bro now talk to each other!" Fresh pushed Error towards me.
"Hi Error!" I meowed. "What do you want?" he was annoyed. "When I was talking to Sci, I've been thinking..." I thought for a bit. "I wasn't asking for an actual response!" he looked at me. "When he told me every choice inside a universe splits making two other universes...the choices don't belong to a single universe so they exist inside the multiverse..." I thought for a bit more. "Does that mean every time you destroy a universe...you create a new multiverse?" then he started to glitch. "Did I break him?" Fresh nod. "I should probably take care of him for a while...you can go to other universes if you want." Fresh pulled Error upstairs. I opened a portal then went into the omega timeline, they were right...this place never seems empty...