the Truth is stranger than fiction... | Elon Musk signs the "grimoire", joins Royal Society... @thetruthisstrangerthanfict4367 | Uploaded July 2018 | Updated October 2024, 3 hours ago.
So obviously, he was joking when he referred to the book as a "grimoire" in a tweet announcing his recent induction into the Royal Society... But then again, if you understand what the Royal Society is actually founded upon, you know that it's not really a joke after all.

twitter.com/eIonvcmusk/status/1019289928373604353