The twins fought Bill for many years. But, one day that all ended.
Mable and Dipper sat on the ground outside of the mystery shack. They were both having a pretty good day, and Mable was even singing,"LA LA DA DA LA DA!" Dipper was slightly annoyed and made a face. Mable sang even louder! Finally, Dipper joined in too. "LA LA DA DA LA DA," they both sang together.
Suddenly, Mable stopped singing. A fright filled panic covered her face as she stared up at the sky where Bill Cypher stood tall, ready for battle. "I told you I'd get my revenge on you kids someday!" Bill's voice echoed through the air, causing a frightening tint to the happy mood.
He zapped Dipper first, tying him up. Then Mable, causing her to drop dead. "NOOO!" Dipper couldn't believe that he had just lost his best friend; his sister! He suddenly wished that he had payed more attention to her stories and spent more time with her.
Bill floated over to Dipper and picked him up, still tied up. "Best for last!" Bill's voice felt like fire on his skin. He had killed his best friend! Bill zapped Dipper and he caught on fire. Dipper died after 3 minutes of being scorched.
That day, the twins learned that they were more than just best friends, or siblings; they were soulmates.