Tesla chief executive Elon Musk has a well-known rivalry with Amazon’s Jeff Bezos, and following news that Amazon will purchase self-driving startup Zoox, Musk has once again poked fun at Bezos.

Over the weekend, replying to a tweet from the Financial Times linking to an article about Amazon’s acquisition of Zoox, Musk tweeted that Jeff Bezos is a copycat, using a cat emoji instead of the word ‘cat’.

Read More: Amazon Reportedly Buys Self-Driving Startup Zoox For Over $1.2 Billion

While details about Amazon’s purchase of Zoox remain scarce, it is understood that the e-commerce giant will pay more than $1.2 billion for the company. It is reported that Amazon may work with Zoox to create a ride-hailing fleet that could compete against Google’s Waymo self-driving division and may also look to integrate autonomous technology into its delivery fleet.

Amazon purchased Zoox roughly two months after the latter was forced to lay off 100 employees due to the coronavirus pandemic. The acquisition means a majority of Zoox investors will get their money back with some making a positive return. Key investors include Lux Capital, DFJ, the Canada Pension Plan Investment Board, and Atlassian co-founder Michael Cannon-Brooks.

Musk and Bezos’ rivalry dates back to 2013, when Musk’s SpaceX won out over Bezos’ Blue Origin to take over the Launch Pad 39A at Kennedy Space Center. In 2015, the two butted heads over Bezos’ claim that Blue Origin was the first space company to successfully launch a reusable rocket.

Regardless of how Musk may feel about Bezos venturing into the world of self-driving technologies, the industry could do with some more competition.

Zoox testing in Las Vegas

Opening images via Wikimedia Commons, Heisenberg Media and Steve Jurvetson