All the precambrian animals were weird ;P
Yes, although the fossil record for the precambrian period is scarce. See related link.
Jellyfish intervirbrates
The animals in the Precambrian Period were soft bodied animals. This Era was dominated by single celled organisms: algae, bacteria. Also in existence were jellyfish, spiders, crabs, and worms.
jellyfish-like animals, sea pen, and bacteria.
The appearance of complex, multicellular animals.
Animals that lived during the Precambrian times were single celled animals such as stromatolites,(blue-green algae).The earliest forms of invertebrae animals were also in the Late Precambrian.
As far as we know for the majority of the Precambrian super-eon the only life on earth was bacteria.At the very end of the Precambrian multicelled life evolved. Amonst them jellyfish, invertibrates, sponges and pretty much a prehistoric version of most sealife today. There is also very suggestive evidence for simple plant life in the form of green algae in the Precambrian.
Late in Precambrian time
Examples of Precambrian animals are Brachiopods (aka lamp shells), Anthropods like spiders and crabs, jellyfish, sponges, and squids. There were also flora and fauna, of which 70% of their population was wiped out (Precambrian Mass Extinction). Most of the animals in that era were marine, soft-bodied organisms.
single-celled organisms and soft, boneless animals
Precambrian is BEFORE the Cambrian period!
Animals without backbones, called invertebrates, developed near the end of the Precambrian. Imprints of jellyfish and marine worms have been found in late Precambrian rocks. Because invertebrates were soft, they weren't easily preserved as fossils. This is one of the reasons why the Precambrian fossil record is so sparse.