Elon Musk unveils Tesla Motors Inc.’s newest products in Hawthorne, Calif., on April 30. (Ringo H.W. Chiu/AP)

Perhaps it’s not surprising that entrepreneur/futurist Elon Musk and Google CEO Larry Page are fast friends.

The two men, as Mashable notes, are similar in age, demeanor and otherworldly ambition.

The nerd bros have tons of overlapping interests, so much so that they enjoy getting together with Google co-founder Sergey Brin at a “secret apartment” owned by his company to bat around reality-altering ideas, according to “Elon Musk: Tesla, SpaceX, and the Quest for a Fantastic Future,” a new authorized biography written by Ashlee Vance.

For example: The tech wizards have discussed building a commuter plane that continually circles the globe for fast transport.

Musk, as Page tells the biographer, even crashes at the executive’s home when he’s in San Francisco.

[The 22 most memorable quotes from the new Elon Musk book, ranked]

“He’s kind of homeless, which I think is sort of funny,” Page is quoted as saying. “He’ll e-mail and say, ‘I don’t know where to stay tonight. Can I come over?’ I haven’t given him a key or anything yet.”

There’s just one nagging problem between the two men. Nothing serious, though, just a little tiff between old buds about the future of the universe, really.

Musk thinks Page may be “building a fleet of artificial-intelligence-enhanced robots capable of destroying mankind,” according to the book.

Then again, who doesn’t have a friend with apocalyptic tendencies, right?

Besides, it’s not like Page is doing it on purpose. Musk thinks his buddy is “fundamentally a well-intentioned person and not Dr. Evil,” the book notes. But it’s Page’s “nice-guy nature” that has his friend sweating bullets as he lays in bed at night.

“I’m really worried about this,” Musk is quoted as saying.

“He could produce something evil by accident,” he adds.

Admittedly, the whole thing is a bit awkward. These guys aren’t just friends — they’re friends with some serious benefits.

“Google,” Vance writes, “has invested more than just about any other technology company into Musk’s sort of moon-shot projects: self-driving cars, robots, and even a cash prize to get a machine onto the moon cheaply.”

And Page, according to an “Elon Musk” excerpt published by Bloomberg, nearly bailed Tesla out in 2013 when the company was veering towards bankruptcy. When sales suddenly improved, Musk eventually walked away from the $11 billion deal for Google to acquire the electric car company, which would’ve been the second-largest in Google history, according to Mashable.

[Elon Musk: Human-driven cars may be outlawed because they’re ‘too dangerous’]

“Google has acquired more than half a dozen robotics companies to date,” Mashable points out, “but the company’s ultimate goal for robots is unclear.”

Though his friend worries that he may be bringing about the end of mankind, Page told Vance the feeling is not mutual. He is quoted as saying he finds Musk “inspiring” because of his willingness to invest time and money in companies that aim to solve some of humanity’s greatest challenges.

Musk, meanwhile, has been warning about the dangers of artificial intelligence for months.

In October, at the MIT Aeronautics and Astronautics department’s Centennial Symposium, Musk amped up the alarm, saying: “I think we should be very careful about artificial intelligence. If I were to guess like what our biggest existential threat is, it’s probably that. … Increasingly scientists think there should be some regulatory oversight, maybe at the national and international level, just to make sure that we don’t do something very foolish.”

He added: “With artificial intelligence we are summoning the demon.”

Tesla chief executive Elon Musk warned that artificial intelligence could be our biggest existential threat and believes there should be some regulatory oversight at the national and international level, while speaking at the MIT Aeronautics and Astronautics department's Centennial Symposium in October 2014. (MIT Dept. of Aeronautics and Astronautics)

As far as AI-fearing technologists go, Musk is far from alone. In recent months, Bill Gates, Stephen Hawking and Steve Wozniak have all sounded the alarm on the dangers of AI.

See here: Bill Gates on dangers of artificial intelligence: ‘I don’t understand why some people are not concerned’

And here: Stephen Hawking just got an artificial intelligence upgrade, but still thinks AI could bring an end to mankind

And here: Apple co-founder on artificial intelligence: ‘The future is scary and very bad for people’

“I am not alone in thinking we should be worried,” Musk wrote during an online discussion in November, according to Mashable. “The leading AI companies have taken great steps to ensure safety. They recognize the danger, but believe that they can shape and control the digital superintelligences and prevent bad ones from escaping into the Internet. That remains to be seen.”

A new book on Elon Musk offers an unforgettable look at the leader of Tesla and SpaceX. Here are some anecdotes and quotes that stood out. (Matt McFarland and Tom LeGro/The Washington Post)