Essexella asherae
Pennsylvanian
Francis Creek Shale
Pit 11, Will Co.
Illinois, USA.

Although long referred to as a jellyfish, Essexella asherae is now generally interpreted as a cnidarian closely related to modern sea anemones. Its preservation is remarkable because animals lacking hard skeletons rarely survive the fossilization process.
Big 60mm in 92mm paired concretion