This is the smartest AI in the world,” Musk said. He did not mention the chatbot’s viral posts praising Hitler and calling itself “MechaHitler.”

X eventually deleted many of the obscene posts. Hours later, on Wednesday, X CEO Linda Yaccarino resigned from the company after just two years at the helm, though it wasn’t immediately clear whether her departure was related to the Grok issue.

“We are aware of recent posts made by Grok and are actively working to remove the inappropriate posts,” the Grok account posted early Wednesday, without being more specific.

The release of Grok 4 comes as the chatbot is currently mired in controversy over recent antisemitic posts.