These "living machines," born from the Fribulan mother, are the equivalent of our resource extractors. Harvesters, ridden by Fribulan soldiers, vacuum up mineral resources and process them into bubbles, which are carried back to the mother and then shuttled up to Frib ships by their transporters. Fortunately, harvesters aren't very tough. They can easily be destroyed with automatic lasers. Just watch out for the other Frib usually found protecting the harvesters.