If you think about, we "humans" are about as strange as creatures can get. We breathe oxygen, which is a corrosive gas. Metal exposed to oxygen starts to rust. Some common foods we eat like apples contain arsenic and other poisonous substances. By the time we're adults, we have more foreign microbes living in our bodies than human cells. We're pretty scary as a species all right. To other alien life out there, we're probably going to seem like extremely mutant freaks.