This paper toy is Bill Cipher, a dream/mind demon that can enter a person's subconscious, from the Disney's animated television series Gravity Falls, the papercraft was created by Moomuu. Bill Cipher can be summoned using an incantation found on his page in Book 2: "Triangulum, entangulum. Veneforis dominus ventium. Veneforis venetisarium!", which, translated from it's original Latin, comes out to: "Triangle - I invoke you. I come to the defensive barrier of the mind. I will see the barrier destroyed."
Bill is a yellow, triangular creature that bears a strong resemblance to an Egyptian Pyramid. He has a single large eye rimmed with four short lashes on its top and bottom. He moves around largely by floating about, and rarely actually stands on his own two feet. He has thin, black limbs, wears a small, black bow tie, and has a tall, thin, black top hat that he "wears" which floats just above his head. His arms do not seem to be in any fixed position, and can be moved along his perimeter without any difficulty. He has also been seen carrying a small, black, cane.
Bill is a fast-talking and physically irreverent demon who finds most things amusing. He's outrageous and outlandish. Though he may come across as simply annoying, he's not to be taken lightly; when angered, he's a force to be reckoned with. [Source: wikia]
You can download the papercraft toy template here: Gravity Falls - Bill Cipher Free Paper Toy Download