Later that night, Frisk had a strange dream... no, more like a vision.
Frisk found herself in a seemingly pitch black room. Until she noticed the dark greenish grid around the room. She was is a battle sequence, but with whom? Then, a large, dark grey mass of... something, came out of the ground in front of Frisk. This caused her to jump back a little, because no monster had appeared like that before! The strange blob began to form into a skeletal, humanoid figure. Similar to that of sans and papyrus, though the brothers had never mentioned this stranger. Frisk was contemplating on how or why she was summoned to a battle when she clearly remembered going to sleep, and nothing else, when the fully formed monster spoke.
"Why, hello Frisk. I have been waiting a long time for a moment to speak with you".
"What!? How do you know my name!? Why have you brought me to a battle!? Who... WHO ARE YOU!?" Frisk yelled, The sight of the blob after what was supposed to be a good night's rest put her under a lot of stress. "Please, do not be alarmed. I am not going to harm you." The monster reassured. "You may call me W.D. Gaster, and I have a knack for listening." Gaster concluded. Frisk protested, "so wait, you were listening in on my conversations with-"
"Sans and Papyrus? Why yes, I have been studying you for a while now.". Gaster interrupted. "Well, isn't that just a tad bit creepy?" Frisk argued. " It can be very unsettling for someone like you, I can tell. But at this point, I would not put my reputation over my research.". Gaster retorted. "And why is that?" Frisk asked. Gaster chuckled. "Well, to put it simply, I don't really exist in this reality. Or at least, I don't anymore.". Frisk was dumbfounded. "WHAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAT!?"
"Would you PLEASE be quiet!?". Gaster barked. Frisk quickly silenced herself. "I only have a couple of seconds left before I must go back to the void. So I must cut to the chase quickly." He continued. "It's about Sans, your friend. The fact is that you don't know nearly as much about him as you think. He's not even a m- NO! not now!". Gaster's time was nearly up. "alright. I can't tell you everything now, but I can give you some clues before I go. Whenever you can, make your way to San's room. He has a drawer with a silver key, that key is used to unlock a secret room in the basement. DON'T FORGET!" Gaster commanded. "When am i going to see you again!?" Frisk cried out, but it was too late. Gaster had already disappeared, and she could feel herself waking up.