Rick and Morty's fourth season is crammed full of celebrity guest cameos, but perhaps none as surprising as the big guest star in "One Crew Over the Crewcoo's Morty." None other than Tesla, Inc. CEO and co-founder Elon Musk stopped by to help Rick Sanchez hatch his latest ridiculous scheme. And in the process, Musk finally explained the origin of a bizarre Twitter joke from earlier this year.

Musk voices a character named Elon Tusk, who's basically just an alternate universe version of himself with large tusks jutting from his lower jaw. But as Elon Tusk himself admits, the tusks have kept his ego and check and make him a more agreeable ally than his non-tusked counterpart would have been. Rick and Morty recruit Elon Tusk to carry out a very complicated heist operation (read our Rick and Morty review for more on how that turned out).

Musk's guest appearance finally answers one of the weirder (if minor) mysteries of 2019. As Time points out, Musk turned heads back in March 2019 when he briefly changed his Twitter handle to "Elon Tusk," with analysts speculating Tusk was teasing a deal with fellow billionaire Warren Buffett or hinting at a new factory being opened overseas. Instead, it seems Musk was simply dropping a clue about his upcoming Rick and Morty appearance.

This episode is strangely well-timed, given that Musk and Tesla have been back in the news lately. Tesla unveiled its unusual new "Cybertruck" vehicle, with a starting price of $39,900 and an expected production start in late 2021. The Internet hasn't exactly given the Cybertruck a warm welcome.

For more Rick and Morty fun, check out our unboxing of the D&D vs. Rick and Morty starter set and our breakdown of Season 4, Episode 2's big Jerry moment.

What did you think of Musk's cameo? Let us know in the comments!

Jesse is a mild-mannered staff writer for IGN. Allow him to lend a machete to your intellectual thicket by following @jschedeen on Twitter.