Retcon: the Xenomorphs were a form of life based around fluorine chemistry, which provides a physically plausible mechanism for how their blood eats through any

Retcon: the Xenomorphs were a form of life based around fluorine chemistry, which provides a physically plausible mechanism for how their blood eats through anything. Of course that breaks the idea of them incubating in humans, since their biochemistry would react explosively with ours, but that never made sense anyway.