Papyrus X Undyne

An AU...?

Undyne's perspective:
After the cooking lesson I left It Papyrus' house and walked home through waterfall I listened to the Echo Flowers recite a story as I walked through. I wasn't paying attention so I ended up in the Temmie Village. I walked home as usual it felt like something was off, but I didn't think about it. I saw Frisk walking with monster kid, they looked like they were having fun. I walked a little farther till I heard Frisk and Kid scream, I ran back to where I saw them last. They both looked confused, for some reason.
"What happened?" I asked.
"Well, we were just walking and all the sudden this weird portal appeared," Frisk answered.
"Yeah, we saw Frisk through it," Kid said.
"I had Flowey sitting on my shoulder, he was helping me," Frisk finished.
"The portal closed, I'm assuming," I replied.
"Yeah," Frisk answered.
"So your both okay, I gotta go, bye," I said, as I started to walk away.
*Le Time skip brought to you by ScIeNcE*
I walked into Alphys' lab, I decided to talk to her in persona about the portal thing. When I was about to walk in I heard a weird sound I turned around and saw Alphys and I standing in front of her lab. A portal, what they really were telling the truth. The other Me was wearing a half top, for some weird reason and Alphys looked like a mad scientist.(media above)
"The human is just leaving Snowdin, the skeleton brothers were unable to stop her," the other Alphys said.
"Don't worry ill stop her no matter what it takes," the other me responded.
"You'll have t-them for s-s-sure Undyne," Alphys replied.
"Well, I'll get back to my post," the other me said. The portal closed, I was dumbfounded, what the heck did I just witness. I went inside Alphys' lab Sans was there too.
"U-Undyne, did you see a portal too?!" Alphys said.
"Yeah. I saw one just outside!" I answered.
"Well, I've d-developed a th-theory, these portals we're seeing are one way windows to AUs-,"
"WHAT THE HECK IS AN AU???!!!" I asked loudly.
"Cool down, I know you need to, we're in Hotland anyways," Sans said.
"Well AU stands for Alternate Universe, since we're looking at them and the others aren't reacting to the portal, I'm assuming it's one way," Alphys replied.
"Ok so what are we calling this AU?" I asked.
"Sans says we should call it Underfell," Alphys replied.
"It has a nice ring to it, but why underfell," I asked.
"Well according to the many 'portal reports' our doubles are very abusive and mean to the human in that universe," Alphys answered.
"Okay, I've heard enough, I gotta get going bye," I said as I started exiting the lab.