A fake image of Senator Mitch McConnell looking sick in a hospital bed went viral this week, but Google’s SynthID watermark system caught it red-handed. Snopes confirmed the image was AI-generated after detecting SynthID’s invisible signature. The watermark, launched in 2025, survives even when images are screencapped and shared across platforms like Reddit and X. It works only when AI tools voluntarily embed it—Gemini models have it built in, and OpenAI joined the program in 2026. The McConnell hoax tapped into real public concern about his health, but the watermark proved the image was fake. Why it matters: This shows that opt-in watermarking can actually work in the wild, but its effectiveness depends on widespread adoption, which remains incomplete.