Beginning approximately 2.5 billion years ago, this Eon saw what was potentially the most severe mass extinction in Earth's history, known as the "Great Oxygenation Event." The amount of free oxygen in the atmosphere skyrocketed after the various oxygen sinks became saturated, killing off the vast majority of life which had adapted to a low oxygen environment. Later, between 650-800 billion years ago (still during the Proterozoic Eon), the Earth entered into the so-called "Snowball Earth" period during which the surface was almost entirely frozen (this is all, of course, theory). I remember first hearing of the 'Snowball Earth' during a college geography course and have ever since longed to explore that notion musically. Today is the first attempt, though I think I've hardly scratched the surface.
Planet being overrun by pesky anaerobes? No problem! Try new OxiClean and in no time your atmosphere will become a harsh an inhospitable wasteland effectively ending the reign of the anaerobes!