Bergaueria
Bergaueria is an Ediacaran–Silurian trace fossil believed to represent the dwelling trace of Cnidarians (Actinia – sea anemones).  It likely caused mixing and fluid exchange into the sediment (bioirrigation).
Similar traces (Cheiichnus) can be made by rotational movement of arthropods.

References 

Ediacaran life
Trace fossils
Silurian life