Disclaimer: Undertale belongs to Toby Fox.

Entry 5

Frisk hasn't talked to me again yet, despite me acting like I was "opening up" to my "feelings". But today, they brought over Nabstablook. I had forgotten that there were ghost monsters, but this one is the one I wanted to see the least. At least he'll talk to me.
Nabstablook can see me and hear me when he goes into his invisible form, but then Frisk can't see or hear him. Knowing this fact, I played a trick on Frisk at one point, pretending to kill an invisible enemy. That Frisk thought I was hurting his little ghost friend! The look on his face was priceless! I was just howling with evil laughter! Then Nabstablook showed that he was fine, since ghosts are incorporeal and can't be harmed. He was in on it with me.

Oh man, I can't believe I got that shy ghost to get in on that prank! HA! Can't be mad at me now, Frisk!
Oh, and Blook (I'm just gonna call him that, it shortens things up a bit) said I was nice. Me. Nice. Yeah, I don't think so.

After that ordeal, I asked Frisk to bring over Mettaton some time (he's a ghost in a robot, right?) and Frisk beamed. He is really happy at me "making friends" now. Yeah right. But get this. After I asked him that, he said:
"Sure thing, Sis!"

"Sis"?

Frisk thinks I'm like their sister?! What did he think would let him call me "sis"? I'm evil, he's nice. I hate everything, he loves everything!
Oh, well. I can deal with that later. Weird, though.

And yes, of course I'm a girl.
And yes, of course Frisk is a boy.
That's like so obvious. Duh.

Entry 6

Frisk just RESET.

Not everything, but the whole day with Nabstablook. What could cause him to do something like that? He said he would only RESET if it was really important.

What could have caused this?