Colloquially known to Arthropoid monsters as "(a case of) the Jeepers Creepers," this parasitic fungoid can complete its development only in the body of an Arthropoid, or more slowly, in a pure human. Once mature, the monster commandeers the host's mummified corpse, externalizes its ocular brain pods and begins producing thousands of spores. Any organic and semi-organic being is susceptible to infection, but non-human, non-arthropoid hosts are reduced to little more than blind, mindless puppets of the parent fungus, producing no viable spores of their own.
Sporrendous may retain the memories and personality of their original host, but experience a sense of having been "awakened" or "set free," a feeling they are often eager to share. Nonviable host species are regarded by some Sporrendous with pity and disgust; perpetually blind "wretches" suitable only as personal slaves.