huge huge biology Mind pineapple

what a coincidence, my teacher mentioned this today because in most books it says that all multicellular animals do this cellular respiration process(glycolysis, krebs cycle and electron chain transport thingy where oxygen is needed to make ATP and ya.) but now we have pluricellar animals that do not need oxygen, soo in other planets this might also be posible, doubt their metabolism is as good as ours though lol.