Seven. Seven human souls and King ASGORE will become a god. Six. That's how many we have collected thus so far. Understand? Through your seventh and final soul, this world will become transformed. First, however, is as customary for those who make it this far... I shall tell you the tragic tale of our people. It all started, long ago...
...No, you know what? SCREW IT! WHY SHOULD I TELL YOU THAT STORY WHEN YOU'RE ABOUT TO DIE!?! NGAAAAAHHHHHHHHHHHHHHHHH! YOU! You're standing in the way of everybody's hopes and dreams! Alphys's history books made me think [that] humans were cool, with their giant robots and flowery swordswomen. BUT YOU? You're just a coward! Hiding behind that kid so you could run away from me again! 

heh... It's nothing... No... s-somehow, with just one hit... I'm already... Already... D... damn it... Papyrus... Alphys... ASGORE... Just like that, I... I've failed you. No... My body... It feels like it's splitting apart... Like any instant... I'll shatter in to a million pieces. But... Deep, deep in my soul. There is a burning feeling I can't describe. A burning feeling that WON'T let me die. This isn't just about monsters anymore is it? If you get past me, you'll... Destroy them all won't you? Humans... Monsters... Everyone... Everyone's hopes. Everyone's dreams. Vanquished in an instant. But I WON'T let you do that. Right now everyone in the world... I feel their hearts beating as one. And we all have ONE goal. To defeat YOU.

Human. No WHATEVER you are. I, UNDYNE will strike you down.

You're gonna have to try a little harder than THAT.

Listen up, human. We're not just going to be friends. We're going to be ... BESTIES.