For lack of knowledge about the subject (even though early animals are really hot), I invite you to go to Pharyngula to read about vendobionts.
From my personal experience, vendobiont seems to come from the Vendian period (610 to 540 mya) and biont–essentially meaning “living thing from the Vendian.” Which I think is a really fun way to say that, when they first named this group, they had absolutely no idea what other groups they are related to.
Note: On my “A Correlated History of the Earth” poster (Pan Terra Inc.), the scale changes at the Vendian-Cambrian boundary.