The Great Collapsing Hrung Disaster of Gal./Sid./Year 03758 which wiped out all the old Praxibetel communities on Betelgeuse VII is shrouded in deep mystery; in fact, no one ever knew what a Hrung was nor why it had chosen to collapse on Betelgeuse VII particularly.

Ford Prefect's father/uncle was the only man on the entire planet to survive the Great Collapsing Hrung disaster, by an extraordinary coincidence that he was never able satisfactorily to explain, a lack which led to considerable social embarrassment. Ford's Betelgeusian nickname, Ix, was based on this fact.