This is a card game where up to six players take turns to evolve fish from the Cambrian era up to the Carboniferous era. The title comes from a geologists mnemonic for the Earth's geological eras. Players have a hand of cards which depict many aspects of evolution including species of fish; events such as major catastrophes and changes to the plankton species; breeding and feeding; genetic mutations and advantages. Each game lasts 6 rounds and players try to evolve the most advanced fish they can before inevitable extinctions reduce their populations to dust.