First appearance: Mysterious Five Project (Irregular Show)Latest appearance: Mysterious Seven Project (Binary Time)
Bill is an insane and physically irreverent demon who finds most things amusing (although no one is really sure why). He's outrageous and outlandish, as well as a quick talker and thinker. 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. He can be summoned using an incantation found on his page in Journal 2 under certain conditions: "Triangulum, entangulum. Veneforis dominus ventium. Veneforis venetisarium!", which, translated from its original Latin, comes out to: "Triangle, I invoke you. I come to the defensive barrier of the mind. I will see the barrier destroyed."
In order to prevent Bill's chaos inside someone's mind, one must light nine candles and place their hand on the victim's forehead. Say the following incantation: Fidentus omnium. Magister mentium. Magnesium ad hominem.Magnum opus. Habeas corpus. Inceptus Nolanus overratus. Magister mentium. Magister mentium. Magister mentium. If spoken the reciter of the incantation's eyes will turn blue and will be brought to the victim's mind on how they picture, where they have to find a way to stop Bill themselves.
In the Mysterious X Project series
The Mysterious Five Project
Bill Cipher briefly appears in Irregular Show to drop the first Irregular Gem, and according to Bloo, he was one of Dr. Doom's followers. He briefly appears at the end of Irregular Show, stating that he's watching, as Serena puts flowers on Solmon Grundy's grave.
The Mysterious Seven Project
Bill Cipher appears to be the main villain of this one.
Standard Special: Laser Eye - Bill shoots a laser at the ground, which will find it’s way to the other side of the stage and cannot move until the move finishes or he cancels it.
Side Special: Nightmare - Bill summons a nightmare at random (British Bulldog, Snake, Scorpion, or a Zombie) and the Nightmare will attack a random character. These Nightmares last a good 20 seconds.
Up Special: Teleport - Bill teleports up onto the stage. This doesn’t work when he’s underneath the stage or too far from the stage.
Down Special: Hamster Ball Shield - Bill gets inside of a Hamster Ball Shield which reflects most projectiles. It reflects three projectiles before breaking.
Super Move: Angered Bill - Bill turns red and begins to flash a few symbols on his now black eye. He then gets really big and brings the characters into a Nightmare Arena, where he can summon powerful nightmares to take them out.