Dipper and Mabel have people thinking their the other twin. Bill and Dipper 16.

Mystery shack

"Mabel have you seen my favorite hat I can't find it anywhere." Dipper said going in the shared attic and stopped when she say Mabel "Mabel is that my hat?" Dipper asked.

"Yep! And your pants, shirt and shoes!" Mabel said looking exactly like her twin except her hair.

"Mabel are we gonna pretend were the other twin like when we were kids?" Dipper said uncertain.

"Yep and...walla!" Mabel said cutting her hair short and threw Dipper a wig.

"Okay but you owe me one." Dipper said putting on a sweater, flats and skirt and of course the wig looking like her twin.

"Mabel I love you!" Gideon said outside the window.

"Mabel..." Dipper warned her twin who was smiling and looking away nervously "Did you do this so you didn't have to go on that pity date?" Dipper asked.

"Maybe?" Mabel said then gave Dipper two I.O.U notes "Please Dipper you are so much better at telling guys how you feel!" Mabel begged on her knees making Dipper rub her eyes and nod making Mabel hug her.

"Seeya later Mabel and please don't tell Bill." Dipper said going out with Gideon who was fouled by the disguise. Bill teleported in the attic.

"Pinetree~!" Bill purred on Mabel's necked making her have goosebumps kissing her neck till she backed away "What's wrong Pinetree? Don't yah want me to mark that silky smooth skin?" Bill smiled getting closer till she kicked him in the shins "Hey what was that for" He demanded.

"Because I'm Mabel you duffus!" Mabel said punching his shoulder.

"Why are you dressed like Dipper?" Bill asked arms crossed.

"So I didn't have to go on a pity date with ugh Gideon!" Mabel said grossed out.

"Well if Dipper has to go on a date with Gideon then you have to go on a date with me!" Bill said tugging Mabel's arm.

"Karma." Mabel muttered.

"Yes karma." Bill agreed "By the way Gideon better not do anything to my Pinetree or else!" He said.