While the Earth above remained frozen, in the oceans below kept relatively warm due to the active volcanic vents the algeas and microbes were taking in enough energy to expend into evolutionary mutations, the first multicellular organisms began to develop alongside more complex cell life forms such as the Eukaryotes. This period of evolution is known as the “Proterozoic Era”. These multicellular organisms being much more complex were able to develop into early flatworms, jellyfish and aquatic mushrooms and would later develop other aquatic plants. The mushrooms which spread by spores would also begin to wash up on land where they were already perfectly adapted to grow, the mushroom to this day resembles its aquatic ancestor having barely changed in design in aeons.