You was In Gravity Falls, You was In Woods, You was alone only by yourself, you decide to summon Bill Cipher it was bad idea, you make deal with him u did mistake, You couldn't say no to him u needed to say yes and do whatever he want and say even if this was dangerous, he can posses/control your body like puppet on strings just stringing ur strings or enter bc u maked deal with him that wouldn't broke, if he posses you ur eyes are cat like-pupils black pupils with yellow eyes and could do whatever he want with your body and even mind and life and etc, you was ghost that have blueish-blue light blue aura like ghost, just watching him, he was testing your body he spoke

Bill Cipher: Welcome Again Gravity Falls!, HAHA!, you have quite not bad body, mortal!, I can say I can be used to it!, you will be useful and your body, your mind, your memories, everything is mine!, I will rule this world again finally I will have this world for my own and do weirdmaggedon again!, I missed these screams from peoples/humans/mortals and chaos and destruction, I can do revenge on Sixer again for what he did to me and even these Pines Twins, Time to spread some chaos to this town!~ he spoke he have sinister evil smile and chuckle a bit, using your body moving, walking testing it