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.”

Built using huge amounts of computing power at a Tennessee data center, Grok is Musk's attempt to outdo rivals such as OpenAI's ChatGPT and Google's Gemini in building an AI assistant that shows its reasoning before answering a question.

In a late-night announcement, X owner Elon Musk unveiled the new Grok 4 chatbot. Here's everything you need to know about it.