Lightbolb(CFMOT) × Bill Cipher(Gravity Falls)

LightBolb is presented in the form of a blue bulb with healing light, but more transparent and blue than real healing bulbs. From episode 4, her color gradually began to change to red. Gradually, LightBolb acquired more and more strange abilities. In CFMOT 6 she changed a lot in character. Her gaze went wild, and her actions became very strange. In CFMOT 7 became completely red and got a tumor in her head. Since then, LightBolb has been constantly buggy and sometimes you can see En in her mouth.

In the opening, LightBolb just stands there, and then rejoices and shows a wide smile. In the opening of CFMOT 7, a red LightBolb stands with her back to the screen, and then turns around with an evil smile. The inscription "LightBolb" is replaced with a red inscription "Imposter".

LightBolb is very cheerful, positive and friendly. She is very active and always tries to find the good in different things. However, despite all this positivity, heartbreaking news can bring LightBolb to tears. The negative character traits of LightBolb are possible naivety and, as shown earlier from the first to the third episode inclusive, being a rather shy person. She has absolutely no enemies, as she has never been in conflict with anyone. To help her team, LightBolb finds unusual solutions that, however, work.

LightBolb is the best cook, so she became a chef among objects (but in the future this position will be occupied by Kratcy). Her favorite dish is rolls, but the rest do not share this love.

Beginning with CFMOT 6, LightBolb's personality became very hyperactive and manic. She could fly and burn with just a glance. In episode 7, LightBolb began to lose control of herself. She suffered from hallucinations. At the end of the series, she is completely possessed by En.

Bill is a yellow, two-dimensional and triangular creature that bears a strong resemblance to the reverse side of the Great Seal of the United States, which in turn consists of the Eye of Providence and an unfinished Egyptian pyramid. The color of his body briefly becomes lighter when he speaks. Often when he appears, the area he appears in takes on a washed-out monochrome appearance. It is unknown whether this effect physically occurs, or if it is simply a visual effect to bring attention to his appearance.

He has a single large eye with a slit pupil, rimmed with four short black lashes on the top and bottom, though sometimes there are three on the top and four on the bottom. He moves around mostly by floating about and rarely actually stands on his own legs. He has thin, black limbs, wears a small, black bow tie and a tall, thin, black top hat that floats just above his head. He has no mouth whatsoever, though has been shown using his eye as one to drink something. His arms do not seem to be in any fixed position and can move along the perimeter of his body without any difficulty. He occasionally carries a small black or yellow cane. The lower part of his body has a brick-like pattern of lines. He has no fixed size and he has been shown to be as small as a hand and tower over the Mystery Shack.

In the book Dipper and Mabel and the Curse of the Time Pirates' Treasure!: Select Your Own Choose-Venture it is strongly implied by the Axolotl's poem about Bill that he's an equilateral triangle: the first verse says "sixty degrees that come in threes", and equilateral triangles have three internal angles of 60° each.[14]

However, when he gets angry, his voice deepens significantly, the color of his body turns red and his eye turns black with a white pupil, (in close-up, his eye shows a red iris.) and everything on his body that was previously black turns white.

When possessing someone, that person's skin becomes pale and their eyes become yellow with black slits.

Bill is a cunning, blasphemous, eccentric, sadistic, psychopathic and physically irreverent being who finds most things amusing, particularly if they cause distress or harm to others. He is outrageous and outlandish, as well as a quick talker and thinker. Though he may come across as simply annoying, he shouldn't be underestimated; for when he is angered, he is a force to be reckoned with as he will unleash his near-omnipotent powers on those unfortunate enough to make him angry. When accused of being insane, Bill proudly agrees with the statement. He is also shown to be somewhat obnoxious, as seen when he makes his presence known to Dipper when the latter is trying to figure out a password within a limited amount of time. Occasionally, his voice tumbles to a lower pitch (usually when emphasizing a statement).

As a demonic dealmaker, Bill is also shown to be a highly manipulative, very charismatic and charming conman being able to easily trick Ford Pines into believing that he was just a humble muse who simply wished to help benefit the human world by providing him with forbidden knowledge when in reality he was only ever using the researcher for his own purposes with the book smart Ford noting that the only person who could've possibly seen the ruse for what it was, was his much more street smart brother Stan Pines, who was himself an expert conman.

Bill is not one who believes in rules. Instead, he follows his own selfish philosophy which means doing whatever he wants without care for the consequences. He thinks of laws and physics as senseless and displays an irresistible urge to break those rules down by causing absolute chaos however he can. The lives he ruins hold no merit to him and he finds amusement in tormenting and turning people's worlds upside-down. He also sees reality as "an illusion" and values its destruction.

When possessing Dipper's body, Bill is shown to be rather masochistic, hurting himself in various ways for the thrill of it.