This is the Remora Unmanned Air Vehicle. It's smaller than regular drones, the size of a large missile. And that's precisely what it is: a remote-controlled weaponised aeroplane. One that is designed to be launched from a large drone.
Like the real remoras, which travel under the bellies of sharks and other large fish, the Remora UAV goes attached to the belly of something like a Predator. When it's near a target, the Remora is released and controlled from a remote pilot so it reaches the objective precisely.
Listen. This is the future: I can imagine a huge drone carrier carrying drones carrying weaponised drones carrying a swarm of explosive micro drones carrying flying smart nano drones that bite enemies necks and suck their blood dry. [Flight Global]