Answer: A starfish-killing drone.
Called RangerBot, the autonomous underwater drone is the new and improved version of a 2015 device created by a research team at the Queensland University of Technology in Australia. Its two main functions are to monitor the overall health of the Great Barrier Reef, and to seek out and destroy the invasive species of starfish that is speeding up the reef’s rapid demise.
Known as the Crown-of-Thorns starfish, these creatures feed on the coral that is native to the reef, and their population has exploded in recent years. This new drone is able to identify the starfish with more than 99 percent accuracy, and then injects them with a lethal chemical mixture that does not harm any of the other reef creatures. It also tracks health indicators and maps areas of the reef.
The device weighs just over 33 pounds and is 75 centimeters long. Its battery lasts up to eight hours, meaning it can stay underwater much longer than human divers performing similar tasks. Additionally, the tablet-based user interface used to operate it takes just 15 minutes to learn.