The Flies are a collection of tiny ships that hover around, collecting resources, and reproduce. Their unique ability is that they can teleport, thus making them annoying if you’re trying to get rid of them. The Flies will be hostile, but are not really dangerous unless they have enough resources to build into a swarm. Even then, they are only really dangerous to weak starter ships.
The Flies are not a playable faction.
Blocks
The Flies have only a tiny number of blocks. They have one small cannon weapon and a thruster block. All other functionalities of the faction are contained in the Command Module, which acts as a factory, generator, and teleporter.
Ships
The Flies have a couple different ship designs, but are all very similar. Small, weak, and annoyingly fast. Their cannon does about as much damage as a drone.
Notes
The Flies Command Module is the only block in the game with the SELFFACTORY feature. This means all Flies can reproduce themselves and do not need a factory.
Flies are not dangerous, but more annoying because they continuously collect resources that you would have used for your faction. Those resources then become more Flies.
Kill the Pests
The Flies Teleport ability allows them to dodge cannon fire, but laser weapons will hit instantly and disrupt them from teleporting even if the laser itself does not kill them.