Hi! Shoutouts to @odessa_the_lemoncorn, who is writing a really really good Bill x Reader also, and my friend Ale! By the way, if you are COMPLETELY LOST on this whole "Bill possing Dipper's body" thing then I would recommend you watch the Gravity Falls episode called Sock Puppet Opera, it kind of explains it. (The full episode should be on YouTube somewhere) Thanks and enjoy!
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It had been storming all day. You hadn't gotten enough sleep last night worrying about Bill. He didn't appear anywhere yesterday at all, even when you tried to summon him. Maybe he really did leave you. You felt a pang of sadness and guilt as you recounted two nights ago. He had seemed pretty upset about something, had you done something wrong?

"Y/n," you heard Mabel say your name and you were snapped from your thoughts, "you okay?"

"Yeah, I'm fine," you mumbled, looking down at the table again. You didn't want to bother Mabel with your relationship problems, not that she would understand anyway. She changed her crush almost every day. "Bill will show up," Mabel suddenly said, quietly, and you once again looked up at her in surprise, "How did you--"

"--don't worry y/n, I know all about love. At least the family kind. Whenever Dipper and I get in a fight he goes away too, but he doesn't stay angry for very long." She smiled at you and you grinned back. Mabel was an amazing friend. "Speaking of Dipper," you pointed out, "where is he? I haven't seen him all day." Almost on cue you saw Dipper walk through the door. He had really, really bad dark circles under his eyes and a bloody nose. Also, were those...forks in his arm?! "Hello sister, y/n," he said and sat in one of the wooden chairs between you and Mabel. There was a short silence before you handed him a tissue for his nose. "You're covered in blood," you said quietly and he laughed. That was weird. "Listen, Dipper," you said, "I'm sorry about yesterday. I know you like me but I don't feel the same way. I want to stay friends."

"Who do you like, then?" Dipper asked. His voice sounded strange, maybe he had a cold? He sure looked like it, he was paler and skinnier than ever. "Um...I don't really want to say," you answered, looking away, "you would be pretty upset if I told you."

"She likes you!" Mabel interjected, and as soon as the words came out she slapped a hand over her mouth. "Sorry," she said, a little softer. You sighed roughly and rolled your eyes a bit. You should have known Mabel wouldn't be able to hurt her twin brother's feelings. Now Dipper would be furious when you told him that it was a lie. Now or never, facing his wrath and lecture. Instead of recieving the long scolding speech or for him to start crying like you expected, you just got a chuckle and frown from him. "Okay," he said kind of mysteriously and turned to Mabel, wiggling his fingers as he said, "by the by, Mabel. Have you seen any rope lately?"

"Um, I think Stan has some in the utility closet," Mabel said, and Dipper walked away, slapping himself a few times as he went. "Something's wrong with Dipper," you stated and Mabel just nodded in agreement. "I'll spend the day with him if you want," she suggested, "I'll try to find out what's up with him!" You two settled a plan that if anything, keep the citrine stone and journal safe, just in case. So Mabel left, calling Dipper's name over and over again. You sat at the kitchen table, sipping your (favourite hot drink) and watching the rain pour outside the window.

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As Mabel ran around the house she came across an open window. A rabbit sat on the little outcove outside it and Mabel couldn't resist the urge to pet it. "Mabel!" The rabbit shouted and Mabel screamed, flailing her arms everywhere. "It's me, Dipper," the rabbit said, "Bill ha my body like last time! Remember the puppet show? Except now I don't know where he is or what he's doing with my body!" Mabel gasped in reply and gave him a thumbs-up. "Don't worry, bro-bro, I'll get him to give you back your body!" With that she ran out and into her bedroom, where Bill was rummaging through a few boxes. "Bill!" She yelled and he turned around, smiling. "Didn't think you would find out so quickly, Shooting Star! You're not gonna tell y/n, are you? Well, doesn't matter if you do, she doesn't like me anyway," he grumbled and turned to face Mabel, punching his face a few times causing his nose to start bleeding again.

"I lied Bill," Mabel pleaded, "she does like you! Not Dipper! I just couldn't bear to hurt Dipper. You have to believe me!" Bill rubbed a hand on his chin and gave her a wide grin. "Hows about we make a deal? I don't believe a word your saying, I'll only believe it if y/n tells me herself. I'll promise not to stick any more forks in Pine Tree's skin...for a small pice," he added. Mabel frowned and clenched her fists. "What do you want? To rip out my organs? Eat my soul? You're capable of some sick stuff, Bill, I don't want any of that!"

"Yeesh kid," he chuckled, "I just want you to let me keep Pine Tree's body for a while. Until tomorrow evening. And I want you to tell me who has the citrine stone."

"Don't you already know who has the stone? I thought you knew everything," Mabel pointed out. "Not only does the stone protect the wearer, it makes it nearly impossible for me or other beings to know where it is," he explained, "it blocks us out, in a way." He extended Dipper's hand, which Mabel shakily took. "Okay," she agreed, "but only until tomorrow evening! No more hurting Dipper!"

"Fine, Shooting Star," Bill shrugged and snapped his fingers, "who has the stone?" Mabel sighed and replied, "y/n. But leave her alone! You can't hurt her either!"

"I'm not going to hurt her," Bill smiled. "What is she going to say once she finds out you possesed Dipper's body? She'll be furious," Mabel shouted, "and when she finds out you know she has the stone? Aren't you worried?!"

"Y/n doesn't love me," Bill growled, "I don't care what she thinks."

"Yes you do!" Mabel said, "And she DOES love you, you're just too stupid to see it!" Bill just shrugged again and went downstairs, only knocking Dipper's head against the wall once. Mabel sighed. She had kept him from hurting Dipper, but they had to find a way to defeat Bill before tomorrow evening!