The Microwave Emitter was an experimental weapon developed by Wayne Enterprises in Batman Begins. The weapon was designed to be used to vaporize large amounts of water using focused microwaves. It was stolen and used as part of Ra's al Ghul and the League of Shadows plan to vaporize the water supply of Gotham City that had been contaminated with Scarecrow's fear toxin to induce the population into a state of panic to destroy the entire city. It was transported around the city in a SWAT vehicle and then moved to the Gotham Monorail train until the plan was foiled by Batman.