Who did this? {Billdip fanfiction}

Chapter 1

---Mabel's POV---
Dipper fell asleep in the car ride back to the Mystery Shack. He must be so exhausted. After the ordeal he went through I'm surprised he made it to the car. Looking at him he seemed a little more pale than usual and his cheeks were reddened. Sweat covered him like a second skin.
I put my hand against his forehead. Yup, he has a fever alright. My hand began to tingle and I pulled it away hissing. He has a high fever.
"Gruncle Stan, Dipper has a high fever." I moved closer towards Dipper and positioned myself so, his head was resting against my shoulder.
"Alright, Sweetie when we get home I'll carry him up. Once I do I'll go to the pharmacy to find some medicine. Do you think you can take care of him until I get back?" I nodded.
We pulled up to the Shack and I unbuckled Dipper and then myself. Racing into the Shack I went upstairs and prepared the bed for Dipper. Then I went into the bathroom and got a washcloth and soaked it in the sink. Gruncle Stan set Dipper down in the bed and pulled the covers up to his chin. I walked over and put the washcloth on his forehead.
"I'll be back as soon as I can be. Take care of Dipper and the Shack until I get back. Do you think you can handle that?"
"Don't worry Gruncle Stan. I've got this. Dip'n'Dots couldn't be in better hands. You have nothing to worry about."
"Alright." He walked out of the room on that note.
I turned my attention to Dipper. My stomach knotted when I saw him. He was pale, he's cheeks reddened, sweat beaded along his skin, he was panting, and his face was twisted in pain. I hated seeing him like this. He let out a groan and his face relaxed a little. Tears form in my eyes making my vision blurry.
"Please be okay Dipper. Come on we defeated Bill. We should be celebrating. Don't. D-don't leave m-me D-Dipper." I sobbed clutching his hand as I leaned against the bed.

---Dipper's POV---*his nightmare*
I was lost in the woods. No. I was running in the woods. Running from what? From who? I stopped running to catch my breath. The whole time my mind was screaming to run. Ignoring my instincts I leaned against a tree. The ground started shaking and I was frozen with fear. It found me. Was all I could think.
The tree I was resting against caught on fire. So did the next one and all the others around the clearing I was in. The sky turned a deep blood red. Everything was quiet after the rumbling stopped. Then the silence was filled will the psychotic laugh that could only belong to one being. Bill.
"Show yourself Bill!" I yelled. Sick of his games. Sick of him.
"Now that's no way to talk to someone. Especially me!" The red sky was soon filled with a black triangle with a single glaring red eye. I began backing away and crashed right into a burning tree. The fire burned my arm and the back of my vest.
"Let's have some fun!" Bill said. He voice filled with excitement and anticipation. I was trembling with fear when he said that.
"Let's see...I know how about we play a game. It an endurance game. Let's see how about I take control of your body again. Then I pretend to be you while I kill everyone in you family."
"Don't you dare try to take my body again. Our deal is off. Also don't you dare touch Mabel!" I yelled.
"Aww, it's cute that you believe that." Bill took over my body and snapped his fingers. The dreamscape changed and I was back at the Shack looking at Bill who was still in my body. He had a knife in his hands though and was surrounded by the blood and lifeless bodies of Mabel, Gruncle Stan, Soos, Wendy, and my parents. Bill left my body and I was back in it. Blood covered my arms up to my elbows. It wasn't my blood though. I felt like I was going to puke. I looked around the room and saw all the gore and bloodshed of my family members. My gaze finally locked onto Mabel except her head was missing. I looked up and saw it mounted on the wall. I screamed as I saw her head. Then everything went black.
---Stan's POV---
I came back from the pharmacy with the over the counter kid's medicine for fevers and colds. When I got upstairs I found Mabel kneeling on the ground with her head resting on the bed and her hand holding Dipper's. Putting the medicine on the nightstand I scooped Mabel up and put her on her own bed. Turning my attention back towards Dipper I touched his forehead. His fever finally broke while I was gone. That's a good thing at least. His face was scrunched up like he was in pain. He's having a nightmare. Should I wake him up? Aw, h-e-double hockey sticks, why not? He needs to take the medicine anyway. I gentle shook him awake and when he came around he sat up instantly gasping for air.
"Yeesh, kid calm down. Musta been some nightmare you were havin' if it's gotcha lookin' like this. I'm glad I woke you up now, here take this medicine you were havin' a pretty high fever earlier." The kid calmed down and stretched out his hand for the medicine. I put two pills in his hand and left to get water. When I came back with a glass Dipper had already fallen back asleep. Poor kid. I left and went to go to bed too.