A Visitor From Outer Space Is An Alien: A Time Traveler From Another Galaxy

Are aliens really exist in this universe? What 'IF' they do, how do they look like and behave? The 'AIR' they breathe in, is it hydrogen, oxygen or some freaky unknown gas element that we have yet to discover it? Are they really more superior to us in thinking and technological developments? Are you ready to intercept them when they are here as FRIEND or ENEMY?