Perplexing Pine Pranks (And a side of Ice Cream)

Based on the Transcendence AU from tumblr - The supernatural is widespread, Dipper has essentially become a demon, and things are extremely bittersweet. During one of his summonings, Dipper, demon name 'Alcor', comes across a 13 year old girl named Cassie who needs help with math. Eventually becoming comfortable, Cassie asks Alcor if he'd like to appear at a sleepover for some fun.