In Earth's fossil record, soft-bodied organisms like jellyfish rarely stand the test of time. What's more, it's hard for any animal to get preserved with exceptional detail in sandstones, which are made of large grains, are porous, and commonly form in environments swept by rough storms and waves. But about 570 million years ago, in a geologic time interval called the Ediacaran period, strange-looking, soft-bodied organisms died on the seafloor, were buried in sand, and fossilized in incredible detail.