The war of words between Elon Musk and Mark Zuckerberg takes a new turn as Twitter-competitor Threads gains more users each day. So much so that Musk is getting a little nasty as he called Zuckerberg a “cuck” on Sunday.

Musk’s comment is likely in response to Zuckerberg’s launch of Threads, a Twitter-like app, which has garnered significant attention and already reached 100 million downloads within a week. As a result, Twitter’s engagement has started declining.

The rivalry between the two tech CEOs has escalated ever since Meta introduced Threads as a direct competitor to Twitter. Both Musk and Zuckerberg have been engaged in a battle to prove the superiority of their respective platforms. Musk’s recent insult, referring to Zuckerberg as a “cuck” and humorously mentioning a “literal dick-measuring contest,” showcases his increasing frustration.

Twitter has also issued a threat to Meta, alleging that the company has hired former Twitter employees who had access to sensitive information, enabling the development of Threads. Meta denies these allegations, stating that their Threads team does not include any ex-Twitter employees.

Threads offers similar micro-blogging functionalities to Twitter, allowing users to publish posts with up to 500 characters and reshare content. However, it lacks features such as direct messaging and story posting, which remain exclusive to other Meta platforms like Instagram.