These fossils were discovered in the black shale of what is called the Lantian Formation in China, and they date back to the first part of the Ediacaran Period, the time when life became big, or at least visible to the naked eye.

"Animals in the Ediacaran Period are almost universally bizarre, and it is very difficult to place them in any modern animal phyla," Xiao told LiveScience. "They may be precursors to modern animals or offshoots of modern animals that don’t have any direct descendants."