tl;dr: Ghost Font encodes text into the motion of dots in a video—readable to humans watching it play, but indistinguishable from background noise in any single frame, defeating screenshot-based OCR and current multimodal AI models like GPT and Claude. It also embeds a decoy message to fool agents with local code execution that might analyze dot motion directly. The creator sees potential applications in CAPTCHAs and as a benchmark for video-native AI perception, and plans to open-source the generator.