Water

H₂O. Water. Water gives life. Life needs water. Science fiction and fantasy aside, everything we know about life requires water for it to exist, to come into being, to persist in being, to evolve, according to both the evolutionary and the creationist paradigms of life.

You may have seen episodes of science fiction series and films in which life somehow has come to be in crystalline or gaseous (not water-vapour) form. There is no evidence for that anywhere, and no science that can even propose it could ever happen. Such episodes have crossed from science and even science-fiction into shear fantasy.