The US military is developing a new weapon, that could be used to wipe out entire armies.
The program, called Replicator, is designed to create cheap, disposable drones that can be deployed in large numbers. The drones would be able to fly in formation and attack targets autonomously.
The military is particularly interested in using swarm drones to counter China's growing military power. China has been investing heavily in its own drone program, and it is now believed to have the world's largest fleet of military drones.
Some experts have warned that the development of drone swarms could lead to a "hellscape" of warfare, where entire armies are wiped out by waves of tiny, autonomous machines.
