In the latest chapter on what appears to be the battle of rich men, Elon Musk mocked Bill Gates on Twitter by comparing him to an emoji of a pregnant man.

The Tesla CEO accused the Microsoft co-founder for short-selling Tesla stocks while declaring a commitment to fight climate change.

Musk said on Friday that Gates wanted to discuss philanthropy possibilities with him, which he answered with: “Sorry, but I cannot take your philanthropy on climate change seriously when you have a massive short position against Tesla, the company doing the most to solve climate change.”

Tesla claims to revolutionize the transportation industry by developing solar-powered cars, although it is still a big question mark on how green Tesla is. Their cars are still regarded as symbols of luxury and not affordable for most people.

Also it is reported that Tesla lacks transparency regarding its carbon emission.

In 2018, for example, the company was fined US$139,500 by the Bay Area Quality Management District because of malfunctioning burners at its Fremont plant that had emitted high levels of nitrogen oxide between 2013 and 2016.