Status: INTERSTELLAR NUISANCE
There are little hard facts known about this menace, which brings the silence of death to whole townships and space vessels. It is not even known where they came from and how many ships they have. They first appeared a few tens of thousands of years ago, shrouded in powerful cloaking, ridiculously hard to destroy, and armed with antiquated weapons. Every attempt at communication since has failed. Their motives are equally unknown - they just exterminate every sentient being and destroy all computers, then disappear, without even looting much. The only sure defense - don't let them hear you.