Elon Musk's first dates with Grimes included driving his Tesla with his eyes closed on Autopilot, a 'Lord of the Rings' quiz, and a box of animal bones

• Elon Musk and Grimes told Walter Isaacson about their first few dates together.

• Musk took Grimes for a spin in his Tesla and quizzed her on "Lord of the Rings," the biographer said.

• The couple has since said they've split, but they have two children together.

Walter Isaacson, Elon Musk's biographer, offered a window into the early days of the Musk's relationship with the singer Grimes on Monday.

In a post on X, the platform formerly called Twitter, Isaacson dubbed Musk's relationship with Grimes a "chaotic subplot" in a quote from his forthcoming book on the billionaire.

The biographer said Musk met the singer, whose real name is Claire Boucher, in an elevator when Musk was with his former girlfriend Amber Heard, but their relationship later blossomed over direct messages discussing the concept of Roko's Basilisk — a thought experiment which theorizes that the creation of AI will lead to an all-powerful being that will punish those that did not help in its creation.

"Musk invited her to fly up to Fremont to visit his factory, his idea of a good date," Isaacson, who has been shadowing Musk for over a year, wrote in his post. "'We just walked the floor all night, and I watched him try to fix things,' Grimes says."