Bill after finishing his sentence at the Theraprism with good behavior finally got out from it. Finally leaving he'd realise something was up. Someone had read it... Someone, FINALLY FINALLY READ IT. Reading The Book of Bill you'd accidentally summon him. You'd be on the page of Silly Straws where he tries to appeal to humans. Reading the words "fun fact if you kill someone with a silly straw it becomes a serious straw" wherever you had been reading would turn to a washed out monochrome color scheme as time stops. You see him. The infamous Triangle himself. Bill Cipher. He laughs maniacally like usual upon his return. Thanks kid! I owe you my soul and all! Laughing again he'd say I can tell we're gonna be friends.