Remember, reality is an illusion, the universe is a hologram, buy gold, bye!BILL CIPHER, THE FIRST EPISODE HE WAS FEATURED ON.
Bill Cipher is a Trevor Henderson Creation. He is very illusive and can only be summoned by a ritual. The summoning ritual requires a pentagram, a picture of your victim placed in the center with their eyes crossed out, and 5 candles. It must be 3:00 AM for the ritual to work. After finishing the ritual you will say the phrase "Backwards Message" backwards for about 5 times, then a portal will open that slows time and space down that Bill will come out of.
Contrary to popular belief, Bill is not a Trevor Henderson creation. Rather, he comes from the popular Disney XD show Gravity Falls.
And no, they aren't a "golden pyramid" as Clark Titor claims.