In this article, a classification of the global catastrophic risks connected with the possible existence (or non-existence) of extraterrestrial intelligence is presented. If there are no extra-terrestrial intelligences (ETIs) in our light cone, it either means that the Great Filter is behind us, and thus some kind of periodic sterilizing natural catastrophe, like a gamma-ray burst, should be given a higher probability estimate, or that the Great Filter is ahead of us, and thus a future global catastrophe is high probability. If ETIs exist in our light cone, it is most likely they exist in the form of ET artificial general intelligence (ETAI). ETAI may be traveling at near-light speed as an explosive wave of intelligence in the form of some nano-mechanisms which could reach us at any moment; may send us potentially dangerous messages with AI-virus payloads; or be near or on Earth in some dormant form. This dormant form could be nanobots, which could act as berserkers, and be triggered when humans unwittingly cross some threshold. If ETIs are nearby and less advanced, they could find our messaging extra-terrestrial intelligence (METI) messages and send their “fleet” to or direct weapons toward Earth. Even extinct ETIs could have left dangerous remnants in the form of AI systems that our civilization may encounter. If our existence is a simulation, this could be run by ETIs. Even a false belief in the existence of ETIs could potentially fuel millennial sects. If humanity is the first intelligence to emerge, it may kill or prevent the existence of all future potential ETI, a different type of catastrophe. Several options to prevent catastrophic risks are connected with ETI: sending requests for help, using random strategies to escape the Fermi paradox, Great Filter prediction, or the hope that ETIs will find the remains of our extinct civilization and resurrect it.