The initial stage of a Tyranid assault often comprises several waves of Mycetic Spores. These ablative bio-constructed organic shells are launched by their thousands into the world's atmosphere by orbiting Hive Ships. The fleshy pods are specifically designed to endure the thermal and physical stresses of orbital insertion and protect their lethal payload from planetary impact. Mycetic Spores are often inaccurately reported as meteor showers by civilian observers, but experienced troops soon learn to spot the distinctive clutch of fiery streaks as the spores breach the upper atmosphere. Once through, the Mycetic Spore alters shape to slow its descent. They are sacrificial organisms, and perish soon after impact with the planet's surface, but each one houses a brood of Tyranid assault beast