For a man who left no official writings, French philosopher Jean-Baptiste Botul cut an impressive swath through the early 20th century. Born in 1896, he befriended Marcel Proust, betrothed Marthe Richard, and associated with Simone de Beauvoir, Marie Bonaparte, Jean Cocteau, Jean Giraudoux, Stefan Zweig, and Andre Malraux. At age 50 he resettled in Paraguay, where he founded a town that observed the principles of Kantian philosophy.

Actually, none of that is true. Botul was invented out of whole cloth in 1995 by journalist Frédéric Pagès and promoted by an “Association of the Friends of Jean-Baptiste Botul,” which published works that supposedly advanced his ideas, including The Sexual Life of Immanuel Kant, Nietzsche and the Noonday Demon, and Soft Metaphysics.

The joke has been so successful that an annual prize has been awarded for a work that mentions Botul. The most famous recipient is Bernard-Henri Lévy, who quoted the imaginary philosopher extensively in his 2010 book On War in Philosophy. He acknowledged afterward that he’d fallen for a “well-rigged” hoax.