Flood spore

Flood Spores are the most basic of Flood forms that are crucial in the formation of Flood hives. Spores are also used as methods of suffocating future hosts and clearing the area of uninfected hostiles. It is not known if spores take a specific form or if they are just any type of floating Flood biomass. Spores linger through the air clogging air filtration systems and making it easier to infect hosts. If a spore lands in an area that can support it, it will form Flood Growth Pods. If the area does not have enough biomass to support a Flood Growth Pod, the spore will spread over floors and walls until it covers as much as it can. It is possible that if a non-infected host inhales or becomes covered with these spores, then the host may be infected or the body will be dissolved into the necessary nutrients demanded for the Flood to create the various forms needed at the time.

Trivia

 * You can see Flood spores in Halo 2 and Halo 3 on levels where there is massive Flood infection.
 * In Halo 3, Rtas 'Vadum, during his argument with Terrance Hood, says that "one single Flood spore can destroy a species"(but it is possible that he meant an infection form).
 * The Special Operations Elite Kusovai was horribly infected when he inhaled too many Flood spores.