Gravity falls return (Bill Cipher X Demigod)

The party I didn't want

I don't own any Percy Jackson characters. All Wrights go to almighty Master Rick Riordan
So I've been here for a month and got used to the new routine. Wake up and go exercising in the forest. Bill comes all the time and annoys me with his offerings but I never excepted them ( except that one time when he possessed me thankfully the Pines noticed and got him out ) but now it looked like he was only coming to hangout. So today is my 15 birthday, but everyone was sooo busy worrying about Bill so I didn't want to bother them. I just send Mabel to another earth to give someone an invitation to come to visit me. I give her the through dimensional pin so she could hand the letter over to him.
Mabel's pov
So Mia asked me to give this letter to this guy in another dimension. Oh, I want to know what's about soooooo much. Anyway, she said to go to the cabin in the camp that has seashells on it and knock on the door and give the letter to the person that will open the door. So I opened the door and there was this really cute guy with a really pretty girl. I gave him the letter and he said: "ohh Mia's inviting us over on her birthday." Wait...WHAT? "What?!" I said. "Oh," he said. "Didn't she told you that it's her birthday?" He said. "No, she didn't," I said. "Well... "He said. "Thanks for bringing the letters and portal pin to us," he said and closed the door. I opened the portal and think about what kind of party I gonna prepare for her.
Mia's pov
So I was sitting in the kitchen, quietly reading and drinking a blue fizzy drink with Dipper (who was reading his journal(of course)). "Whoa surprisingly calm and quiet moment," I said "wonder when's gonna be ruined" the door slammed and I heard Mabel shout: "MIA!!!!!". (A/n: know what show is this from)."There it is, "I said. Mabel came running in the kitchen shouting: WHY DIDN'T YOU TOLD US IT WAS YOUR BIRTHDAY!!! We'll throw a party for you!!". Ok so if it's anything I learned, it is that there's no point to argue with Mabel. So I gave in. "Ok what are you planning?" I asked." i'm gonna decorate, Dipper you prepare tables. Wendy will bring a karaoke machine and Soos is gonna hand over the invitation". "And I'll make food." I said. "What? But it's YOUR birthday"."Oh that's exactly why. I LOVE to Cook. So I was preparing food and listening to music and singed (A/n Song above). I don't like to sing when I'm with someone. And Dipper and Mabel walked on me. "You sing nice," Dipper said. I jumped and accidentally cut myself and let out a curse word in ancient greek. Luckily I just finished preparing food (blue of course(Percy's favorite type of food)) "Whoa." Dipper said and looked at Mabel. "Well maybe I prepared a little too much," I said. "A little?!?" Dipper asked and look around the full kitchen of food. Tones of it. And it was mostly blue. Luckily RIGHT there Mabel chimed in and said:" Dipper Mia needs to prepare for the party." An hour later I was ready and Dipper walked into my room. "Mabel have you saw my ... Whoa.' he said. "What do you think?" I asked. "I... Ughh... You... Me...". Oh come on just because I prefer trousers and a top instead of a dress, that doesn't mean that I can't dress nice! " You look amazing!" He said. I looked in the mirror. I actually looked good. I put on black heels and a black purse ( containing my lipstick/sword, a book, and my phone). My nails were golden and matched my owl bracelet/shield and a necklace with a lucky leaf. Mabel tied my hair in a knot and I put a golden hairband on them. Mabel also put on some lipstick on me ( gonna brush it off in a minute). I wore a black dress with glitter that sparkled like the night sky. I also wore a black jacket that went with my dress. Mabel said: "You look great! Now let the party begin!"