Bolideids

Bolideids are a hypothetical group of organisms that are theorized to have existed in Earth's early oceans. The concept of bolideids arises from the study of stromatolites, which are layered sedimentary structures formed by the growth of cyanobacteria and other microorganisms. Some scientists have proposed that certain patterns observed within some stromatolites could represent the fossilized remains of complex, multicellular organisms rather than solely microbial mats. These hypothetical organisms, termed bolideids, are envisioned as being soft-bodied and possibly sessile, anchoring themselves to the seafloor or other substrates.

The idea of bolideids is highly speculative and not widely accepted within the scientific community. Evidence for their existence is largely indirect and based on interpretations of stromatolite microstructures. Critics argue that these structures can be adequately explained by abiotic processes or by the behavior of known microbial communities. Further research into early life forms and the formation of ancient sedimentary structures is needed to either confirm or refute the existence of bolideids. The term itself is derived from "bolide," referring to a large meteor, perhaps suggesting a sudden or significant appearance in the fossil record if they were ever proven to exist.