"What are you doing here?" Dipper asked nervously. He could feel Mabel shaking beside him.
"You're supposed to be in prison!" Mabel cried, pointing a finger at the small boy with unnaturally white hair.
"And you're supposed to be my queen!" he yelled, raising a clenched fist at her. Waddles snorted as if to disagree with the insane 'psychic.'
"Er dudes" Soos said cowering in fear "I think we should leave now." He started to walk backwards, with Mabel's camera still in his sweaty hands but the boy raised his hand and from the ground behind them emerged large jagged rocks.
"You're not going anywhere!" shouted the boy - who I'm pretty sure you figured out was no one else but Gideon Gleeful. "After the Pines family sabotaged my plans to take over the Shack and I was unjustly thrown in prison, I started to plan my revenge against them. Then I realised that my journal was missing, and who else could have taken it but Dipper Pines?" He glared at Dipper as if he was a vicious cobra rather than a twelve year old boy. "Where's my journal boy?" Gideon asked angrily.
"I don't have your journal!" Dipper said, trying to keep his voice steady so it didn't sound like he was scared.
"Don't lie to me Dipper!" Gideon yelled as he stepped closer towards them.
"How did you escape from prison?" Mabel asked, hugging Waddles tightly. Now that Gideon was free he could take over the shack again, and with the yellow triangle's help he could destroy the Pines family, and Dipper didn't think he could stop Bill again.
"I summoned an old friend" he said, gesturing to Bill Cipher with his chubby hands. "And we agreed to work together one more time" he paused and glared at Bill – probably remembering the time when the yellow triangle had failed to give him Stan's combination to the safe when he tried to steal the deed to take over the shack. "Without failure."
"You can't summon him without the journal" Dipper said.
"He's probably a hologram or illusion thingy" Soos said walking up to Bill and poking him. A red laser beam came shooting out of the triangle's eye and hit Soos in the stomach, making a hole through him; just like what had happened to Dipper on their first encounter.
"No, dude, he's definitely real!" Soos stammered, dropping the camera, and ran behind Dipper, quivering with fear.
"I've read that journal more times than you can count boy!" Gideon said "everything that's written down in there is permanently recorded in my brain."
"Bill has told me everything that has happened with the Pines family in the time I was in prison."
"I told you I'd be watching" Bill said, and images showed up on the triangle.
"And I have made the perfect plan to rebuke the Pines family of their transgression!" He held his little fist in the air. "Be warned Dipper Pines, a great tragedy will befall upon you and your family and there'll be nothing you can do about it! This isn't the last you've heard of widdle old me!" He walked into the trees leaving Bill Cipher with the children.
"Once I have helped Gideon with his plan" he said while readjusting his bow tie, "he will help me with my end of the bargain. Reality is an illusion, the universe is a hologram. Buy gold!" In a sudden flash of eerie blue light the triangle vanished, along with the jagged rocks, leaving just the children standing in shock and fear.
"Oh Dipper what are we going to do?" Mabel asked. Her eyes were wide with shock at the unfortunate event that occurred.
"Let's tell Stan" Dipper said and ran through the forest towards the Mystery Shack, with the others following behind.