Kimberella was a strange creature that could have been a mollusk and lived in the Vendian Period. It had a strange lasagna-shaped foot and a flattened shell on top. It was 1/2" to 4".
Kimberella crawled along the sea floor looking for edible scraps because organisms didn't start predation until the Cambrian Period.
Kimberella was a very weird creature because it had a shell and why would something have a shell if there was no predator? It did have a pretty hard shell.