Musk has tweeted about anime before and admits to not getting that much sleep.
At around midnight PT, Musk tweeted the trailer for "Your Name" saying that he loved it. Wikipedia describes the film as "Japanese animated romantic fantasy drama film" that became a smash hit in and outside of Japan.
Around 1:30 a.m. PT, Musk tweeted "it's time to create a mecha."
A "mecha," in the context of anime, is a giant fighting and flying human-shaped robot with a pilot onboard. The robots, made popular in anime like the "Gundam" series, typically are armed with guns, melee, or sci-fi weapons.
While governments around the world spend hundreds of billions on weapons and defence programs annually, no major military has yet outlined a need for a giant robot that swings a sword.
Though it appears Musk was casually mentioning taking on a sci-fi manufacturing challenge, he has come through on seemingly joking propositions before.
The Boring Company, a subsidiary of Musk's Spacex company, "started out as a joke," Musk said in September.
But now the Boring Company has undertaken a massive tunneling project for the city of Los Angeles with the goal of easing traffic.
The Boring Company is actually already in the business of selling impractical weapons with the flamethrower that quickly sold out, and also started as a joke reference to a film, "Space Balls."
But not all of Musk's Twitter jokes have gone over so well. After Musk's infamous "funding secured" tweet where he said he'd take Tesla private when the stock hit $420 a share, the Securities and Exchange Commission sued him.
The SEC's lawsuit alleges Musk made false or misleading statements with the tweet, and that it may have been a joke for his girlfriend.
"Musk stated that he rounded the price up to $420 because he had recently learned about the number's significance in marijuana culture and thought his girlfriend 'would find it funny, which admittedly is not a great reason to pick a price,'" the filing reads.
Musk agreed to step down as chairman of Tesla's board for three years as part of a settlement with the SEC, though he will remain CEO.
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