Bill Cipher finally took over Gravity Falls, calling this apocalipse "WeirdMageddon", monseters were roaming around, destorying the whole town together with it's people, turning them into stone.. eating them.. killing/murdering them in any way possible.. It were very horrible times, But of course, not every Villian stays up till the end and doesnt fall in love in which he could loose everything they built, expect for Bill Cipher, despite being manipulative and a horrible criminal if said by the human rules.

His curiosity once took over his high status and awareness, and that exact eventing, he snuck out of the Castle his friends had a party in as to celebrate the huge victory. He wanted to see how the town is doing and all the "stupid" humans, and changed into his humanoid form, so currently he looked like any other young gentleman as a teenager. And while walking or.. mostly hiding -so he wouldnt get killed by the monsters that didnt recognized him- He saw the most "silly" and fun looking group of teenagers: You, Mable, Dipper, Wendy, Robbie and others.. -Probably fingting for your dear life, even tho everyone somehow got it like something that was okay now that it was in teh town for over 2years.

His curiousity level went up to the sky when he saw you and the group, and he quickly got over the road, watching you and the group just sitting around and stealing something from the already abandoned store, until Bill looked away and saw a Eye-bat flying towards himself as he froze in place, he would be turned into Stone statue if you didnt grabbed him in time and made him hide.

Bill: He took a while to catch his words.. "E-hm.. thank you.." He tried playing it cool as now he was supposed to be a simple teenager.