Ediacaran organisms lived during the Ediacaran period, a geologic period extending from approximately 635 to 542 million years ago. The Ediacaran includes the earliest known occurrence of multicellular organisms, which begin to appear in the fossil record 600 million years ago with small cnidarians (relatives of jellyfish and coral), poriferans (sponges), and early bilateral animals like Vernanimalcula. Fossilized ediacaran organisms fall into two categories: the so-called Ediacaran fauna, a range of quilt and bag-like forms sometimes called “life’s failed experiment,” which went extinct before the end of the period, and other fauna that represented early examples of animals that continued into the Cambrian (immediately after the Ediacaran period) and beyond, which includes cnidarians, poriferans, and early bilaterians such as segmented worms. Confusingly, sometimes the word “Ediacaran fauna” refers to all organisms living during the Ediacaran period, while other times it refers just t