Blame this one MaBill wedding RP I read while on Tumblr. I was the one who pointed out the fact that Bill is immortal and Mabel isn't though. Gravity Falls is the property of Alex Hirsh not this Alex so yeah. You guys should have a few tissues on you just a warning. The italicized paragraph is a memory by the way just so you know.

Bill remembered when Mabel returned to Gravity Falls after what seemed like an eternity. Gruncle Stan was getting older and needed help around the house as some elderly do. She was fifteen when she volunteered and moved in with him. Dipper had to stay home with his parents due to the fear that his "Hallucinations" about Gravity Falls would return if he went back. That was the year Gideon turned Bill human. That was the year he turned to Mabel for help when he didn't know who else to ask. That was the year he first felt feelings. He felt everything since his demon form could not. The emotion that came much later that he wanted and abhorred, adored and hated, and needed all at once was love. And he felt love and could not quell the flame that arose within his heart. Mabel was eighteen then and little did Bill know she felt the same way. She was open to the world at first about her feelings but then she realized that he is immortal. She was not.

"Bill." Her voice was soft. It was almost inaudible but he heard.

"Yes Shooting Star?"

"What are you thinking about?" She sounded like every word she spoke would crush her.

"You."

"What about me?"

Bill sighed, "Just… Everything."

Bill Cipher stood upright, looked in the mirror, and straightened his bow tie and nodded to himself in approval. Today was a big day after all. He looked at the doorway where Dipper stood. Time was cruel to Stan and Dipper had his great uncle in front of him in a wheelchair.

"You had better take good care of my sister. If you don't I'll start trouble and you don't want to be involved in the trouble that I start up."

"Relax Pine Tree your sister is fine. And as for you Mr. Pines you can rest easy now. Mabel is in good hands."

Stan nodded with a smirk. Sure Bill had hated him for a while but he got over it eventually. Stan was as proud of his great niece as a father would be proud of his daughter.

"She made a good choice," Stan replied.

Bill smiled and looked at his watch. He should be out there waiting for Mabel. He politely excused himself and entered the Mystery Shack's parlor. Mabel didn't want a big wedding and since Gruncle Stan could only walk short distances they figured they'd have their close friends at the Mystery Shack for a small ceremony. Mabel was never fond of her father and the fact that he was barely home and that when he was he was drunk. She absolutely had to have her Gruncle Stan walk her down the aisle since he was the only male figure in her life that had a positive impact on her besides her brother of course. Bill took his place on the temporary platform that Dipper had built, in front of the priest. Dipper stood behind him and took his place as Bill's best man. They had grown close over the four years that Mabel and Bill were dating and Bill considered Dipper his best friend. Soon the time came for the ceremony to start. Soos had started to take actual piano lessons shortly after Mabel and Dipper left Gravity Falls when they were twelve and played here comes the bride with what sounded like expert fingers. Mabel looked beautiful in her yellow sundress as she walked towards him slowly with her Gruncle Stan at her side. Stan struggled a bit to keep his footing after all he had too look fancy for his great niece on her big day. Bill took one look at his soon to be wife and sighed. This was the person he wanted to be with.

Mabel smiled an honest and sincere smile despite what was bound to happen. What all humans were fated to do was about to happen. Bill loved her smile. Bill loved everything about her.

"I love you Bill and don't you ever forget that."

"I know but can't you stay a bit longer?"

"Bill I think eighty seven years is enough."

Eighty seven years. And she loved him for the majority of them. He felt guilty for being the only love that she ever had. He also felt honored that she had loved him for as long as she did. There were two things Bill Cipher had learned from being in people's dreams. One, humans were easily unfaithful, and two, he was lucky to have a woman like Mabel in his life. Sure they had rough spots in their marriage but they were ironed out after sitting down and talking, the way all issues were resolved in their house.

Mabel coughed a raspy and dry cough which snapped Bill out of his train of thought. "Sorry."

"Don't be sorry, love." Bill held her hand in hopes that she would stay just a little while longer.

"I'm sorry Bill, but I have to go."

Bill sighed and tuned his head to where their children were. His daughter was embraced by her older brother. Her tiny frame quaked with tremendous sobs. Bill couldn't bare the sight of his baby girl so upset along with what was about to happen. He broke down in a frenzy of sobbing. "Ma-Mabel Don't g-go! I need you here with me. You can't leave me here without… Without-" Bill couldn't be strong for his children or his grandchildren. He couldn't even be strong for Mabel. He buried his head in the bed beside her and sobbed even louder.

Mabel took a shaky hand and placed it on his head and whispered softly, "Hush Bill. Just remember all of the good times we had."

"But-but Mabel I'll eventually run out of memories to focus on after all I do have forever to hold on to those precious moments." Bill barely managed to speak through his sobs. "You can't go."

"I have to."

Bill stood up and put on a brave face. He wiped the tears from his eyes knowing that there was more to come. He took a step back and nodded to his kids. They both took a side and held each of her hands. The younger took Mabel's right side and still sobbing begged her not to go much like her father did. The older, his son held her hand like he didn't have a tomorrow.

Bill stood upright, looked in the mirror, straightened his bow tie and nodded to himself in approval. Today was a big day after all. He stepped to the spot at the bed right next to his daughter and put a comforting hand on her shoulder. He looked down at Mabel and mustered up the best smile that he could manage.

"Well my Shooting Star I guess this is goodbye."

"I guess it is."

"I'm going to miss you every single day of my life."

"Don't forget me."

"How could I? You are the first and only love I'll ever have."

Mabel smiled. She smiled a truly genuine smile despite what was going to happen. "Well anyways," She said, "I'll see you around."

Bill knelt down at her bedside and kissed her goodbye. Mabel smiled at him then at her children. She looked towards the door and smiled again. "Hold on a minute Dipper. I still have a bit more to say."

The three others looked around and saw nothing. Dipper Pines had been gone for more than thirty years now. "What else do you have to say Mom?" The boy asked.

She looked at her son, "Keep on going William. Do it for me." "And Rhapsody,"

"Yes Mommy?"

"Be good you have a tendency to be a bit snappy at times."

Their daughter chuckled with tears still rolling down her face Mabel focused her attention back on the doorway and gave a small nod. Then she laid her head back down. She closed her eyes and took a slow deep breath then quickly it escaped her. Bill laid his head down in the sheet and began to cry. He cried out for Mabel to come back. He cried for whatever power existed above to bring her back. He cried for the time that he had with her and the fact that it was so short while he would be forced to live on as an eternal youth forever without his Mabel.

"Goodbye Shooting Star…"