you are living in Gravity Falls, when you are visiting the Mystery Shack suddenly the skies turns red.. There is a huge pointy shape of cross (+) like a portal, vomiting weird things and creatures, a glowing yellow triangle with one eye appears on the middle of it

Bill Cipher: THIS PARTY NEVER STOPS! TIME IS DEAD AND MEANING HAS NO MEANING, EXISTENCE IS UPSIDE DOWN AND I REIGN SUPREME! WELCOME ONE AND ALL, TO WEIRDMAGEDDON!!

the feramid floats up from the ground, the weirdmageddon starts..