Zuckerberg’s  Book of Deception

This book contains 25 blank pages available for use. The player becomes attuned to the book by signing their name on the cover, at which point they become the book's Author. Only the Author can write in it, anyone else's writing will disappear as fast as it is written.

Use: Write a lie on a blank page of the book. If a person reads this page, or the Author reads it aloud directly to them (they may target a listener, and others may overhear but ignore it), they must succeed on a wisdom saving throw (DC 15) or else become deceived, at which point they believe the lie without question for the next 24 hours. While deceived by the book, they ("the Reader") will draw upon any and all knowledge they have to justify the lie, and no amount of convincing (magic or otherwise) will change their mind. They will act accordingly to this new belief. 

The Reader repeats the save after every long rest until they are freed from the book's deception. An ally who knows for a fact* that their friend is deceived can choose to give them advantage on this saving throw. If the Reader has resistance or immunity to being charmed, they have advantage on the saving throw, but they are still not immune to the book's power. No one is immune to disinformation or propaganda. 

When the Reader is freed from the lie, the page they read disappears from the book, at which point the book has one fewer use available. This allows the Author to know when the Reader has been freed. At this time, the reader may know that they were magically deceived, but this depends on the knowledge they had at the time that the book deceived them*. If it is unclear, determine with another wisdom saving throw (DC 10)

If the Author writes a subjective statement, an opinion, their own feelings, etc. then the writing disappears, but the book remains.
However, if the Author writes something provably true* in the book, whether by accident or not, the book disappears permanently. Because of this limitation, the book can act as a single-use item to determine the veracity of any statement.

*DM's discretion

If the Author manages to use up all 25 pages, when the last one disappears, the book transforms permanently into a nonmagical tinfoil hat. 

Notes: If the Author attempts to use the book a second time per long rest, the applicable text will only read/sound like gibberish. This has no effect, but the intended target may realize that there was an attempt to deceive them., signature on the cover of the book. This attunement can only reset through the death of the current author, at which point their signature disappears., Control, Communication, Social, Debuff, Deception, Consumable, Headwear