These coasters, made for Mumbai Traffic Police (India), were printed using a special invisible red ink, which spreads only when moistened. They were placed at tables and bar counters in Mumbai’s prominent bars and watering holes.
When a customer places his frosted, moist glass of alcohol on it, the red ink starts spreading and the normal face starts bleeding.
Message at the coaster: Just a reminder: Drunken driving kills.
(via) Thanks Noah