Alcor was bored. Pulling up a CCTV-like AU monitor, he explored some options. For an hour, he ignored any summons and kept searching for a new adventure. Weirdmageddon, Bill is Ruler... Aha! Transcendence with a twist! Alcor marked his find, and popped out of the mindscape. Alcor floated up to his bed room and opened his drawer. He pulled out a box, with a written note stuck to it. It read: Use in case of mishaps during inter-dimensional travel. Inside the box was the mind-wipe gun. Putting it into his coat pocket, Alcor conjured up a rift and changed into his "Bill" form. He walked through.
The other end of the rift opened in front of Stanford Pines' deconstructed portal. Alcor floated out. "Hello, Gravity Falls!" Alcor said to no one. No one heard him. He floated through the floorboards and over to the kitchen.
"Hey, Mabel, at least that crazy Bill isn't here!" He heard Grunkle Stan exclaim. Maybe I'll have some fun while I'm here.
"Or is he?" he heard Grunkle Stan fall off his chair. Changing his color to Bill's familiar yellow-and-black color scheme, he waltzed right into the room, to the terror of the Pines' family. "HAHAHA!" he laughed. "You should see the look on your faces!" He switched to his corporeal form. Their faces changed from terror to awe as they looked upon the thirteen-year old demon laughing hysterically in front of them. Dipper was the first to react, taking Mabel's grappling hook gun out of his pocket, and firing it. Alcor stopped laughing immediately and sidestepped, grabbing the line as it whizzed past, before it could do any damage. The end stopped and hung from Alcor's hand. "Hey, you could really hurt someone with that, and CALM DOWN! I'm not here to hurt any of your family, Pine Tree!" In response, Dipper's jaw fell right open.
Alcor frowned. He had a lot of explaining to do.
Alcor, what have you gotten yourself into? I hope you guys like this, because I wrote it as it came to my head.
I'll post later!