Ghost Font’s ‘human-only’ message was cracked in a day after a single prompt
Ghost Font, a browser-based experiment by developer Eric Lu, briefly looked like a fresh way to hide text from AI systems while keeping it readable to people. The tool turns typed text into a noisy video: pixels forming letters move upward while the background noise moves downward. Humans can spot the message through motion, but frame-by-frame analysis leaves only static snow. Initial tests appeared to support the idea. According to the article, Claude Fable and GPT-5.6 Sol Ultra both failed to recover the real hidden message and instead reported decoy text embedded in the video. ChatGPT 5.5 Pro reportedly spent 19 minutes and still hallucinated a message that was not there. Gemini 3.1 Pro also returned a planted decoy. That edge did not last. Prompt engineer Riley Goodside gave GPT-5.6 Sol a single instruction explaining the motion directions of the letter pixels and the background. After 1 minute and 56 seconds, the model produced the correct message: “RILEY WAS HERE.” The episode turned Ghost Font from a showcase of human perceptual advantage into a test of how close current multimodal AI is to handling motion once the right cue is provided.








