When Dipper got the tattoo he never expected this. Around his left lower arm was a tattoo of Bill's summoning circle, the bottom few symbols cut off replaced with an artistic barrier. He got it in posterity, a reminder of the foe he had helped defeat and the price of messing with demons.
But then the tattoo began to glow gold and burn, it burned like fire that went down to his blood. Pellets of sweat rolled down his face as his entire body heated up. Grabbing his arm Dipper doubled over in pain.
"Ah hahahahahaha." A maniacal laugh rang out inside his head, or outside? It was hard to tell with the pain being nearly unbearable. "It was only a matter of time kid. I knew that eventually I'd find the strength to return. And you couldn't have made this easier if you had put down landing lights."
Another horrible ringing laugh broke out and Dipper tried to cover his ears but the pain grew once again, if that was even possible. Now tears rolled down his face in addition to sweat, and he cried out. Hoping that someone would hear him, Mabel, Mom, Dad, Stan, anyone.
"Sorry kid no one's coming to save you. You were mine the moment you placed that circle on your skin." Cipher voice had definitely come from within his head that time. Pain bloomed across his forehead as painful as his arm. Dippers face was nearly on the ground curled up in pain. Unbeknownst to Dipper the symbol of a golden eye burned across his forehead and opened.
After a minute Dipper stopped shaking as he unfolded and stood taking a few steps, first cautiously then with purpose. His eyes were golden, only black slited pupils broken the even pools. His tattoo still burned golden but no longer hurt. His hand curled and uncurled as blue flames covered it.
"Hello again world, this time there's no one who can stop me. Not when they'd have to kill Dipper to do it." A voice that came was a mix of Dipper and Bills. Followed once again by that horrid laughter, as what could generously be called Dipper's soul shrank within his body becoming untethered and fading.
"What's your name?"
"Dipper Pines."
"How old are you?"
"Nineteen."
"And where's Bill?"
"He's…he's dead."
"Good." Dipper and Mabel sat at opposite sides of the table both still in their pajamas as Mabel helped calm one of Dipper's all to frequent nightmares. Luckily they were both together in Gravity Falls or else he would have had to face them alone. Even though Bill had been dead for nearly eight years Dipper's mind had never really given up the idea the Bill would come back.
"Kids is that you?" Stan padded into the kitchen in his slippers. "Shouldn't you be asleep?"
Stan caught himself as he noticed the look on Mabel's face, a calm that hid worry. And the bags under Dipper's eyes and the redness of the eyes themselves.
"Another nightmare, huh. Look Dipper Bill isn't coming back, you and Ford made sure remember? So there's no need to worry about these nightmares, it's just your stressed brain trying to stress you out more, the teenaged brain is its own worst enemy."
"I'm almost 20 now Grunkle Stan. I'm an adult." Dipper almost laughed and Stan took that as a good sign.
"You're not an adult till your 21 at least." Stan got the glass of milk and made his way out of the kitchen. "Don't let nightmare get you down, you've got us to chase away the demons."
Stan left the room and Mabel stood up. "Let's go back to bed now." Dipper took her outstretched hand and together the returned to the attic they still shared and laid down in their respective beds.
"Thank you Mabel." He whispered, wrapping himself up in the blankets like a child.
"You're welcome." Came the sleepy reply as Dipper turned to face the wall and reminded himself that no matter what he had them.
This is just a short drabble about older Dipper, about the tattoo of the cipher wheel on his arm thing. Inspired by a pic I saw on Pinterest of a drawing by Laura Lora, and by a comic about Dipper and Mabel's post Bill PTSD. I don't have links but both those ideas belong to their original creators not me, I just used them to full in some gaps. Adieu.