In 2020, scientists discovered a jellyfish-like parasite that doesn't have a mitochondrial genome – the first multicellular organism ever found with such an absence. That means it doesn't breathe; in fact, it lives its life completely free of oxygen dependency.

Way to bury the lede...

Motherfucker doesn't even have a powerhouse of the cell...

I guess, at the end of the day, life is just a whole load of chemical reactions. Oxygen is popular for life on Earth, because it's available pretty much everywhere and because it releases energy when combined with carbon, which we've also got a lot of.

Presumably, you could stick any two elements that have an exothermic reaction into a box, give them an energy source with enough activation energy (akin to Earth's Sun), as well as a source of entropy and then, with enough time, life would find a way.