Elon Musk
Elon Musk, co-founder and chief executive officer of Tesla Inc., speaks during an unveiling event for the Tesla Model Y crossover electric vehicle in Hawthorne, California, U.S., on Friday, March 15, 2019. Patrick T. Fallon/Getty Images

When Amazon (AMZN) announced its plans to send 3,236 satellites into orbit to provide high-speed internet to remote regions of the world, Tesla (TSLA) CEO Elon Musk didn’t hesitate to throw a little shade at Jeff Bezos.

In a tweet, Musk called out the Amazon founder, saying he was a copycat in not so subtle terms. The tweet from Musk read the word “copy” followed by an emoji of a cat. The tweet was posted by Musk under an MIT Tech Report article about the project deftly named Project Kuiper to which he tagged Bezos.

The tweet from Musk refers to a similar project that his space-exploration company, SpaceX, has been working on through its Starlink division. In November, the company received approval from the Federal Communications Commission to place 11,943 satellites in orbit to provide high-speed internet to remote parts of the globe, like Amazon’s Project Kuiper intends to do.

Musk’s project is already underway as SpaceX sent two experimental satellites into space in February. Amazon’s Project Kuiper is being led by former SpaceX vice president, Rajeev Badyal, who was fired by Musk in June, CNBC reported.

The CEOs have had their differences over the years as Musk has reacted to Bezos’ Twitter posts in the past, calling out the use of a rare find - a used rocket - in one post, which SpaceX also used for several years in its own operations.

Despite their differences, the men have also supported each other’s endeavors as Bezos wished SpaceX the “best of luck” in February with its Falcon Heavy launch. Musk responded with a kiss emoji while thanking the Amazon CEO.

Shares of Tesla stock were up 1.37 percent as of 9:53 a.m. ET on Wednesday while shares of Amazon stock were up 1.90 percent at the same time.