Hallucinated URLs are non-existent web page addresses that are generated by Large Language Models (LLMs). These URLs may look plausible but lead to 404 errors when clicked. This phenomenon occurs when an AI model, in its attempt to provide a helpful answer, fabricates a URL that it thinks should exist. A key GEO tactic is to identify these hallucinated URLs in website analytics and set up 301 redirects to the most relevant existing page, thereby capturing potential traffic and correcting the AI's mistake.