Hauns prey on sha’az (q.v.) eggs because they contain a substance reducing resistance to mental contact. The eggs allow automatic success for psionic contact and mindlink (except on a roll of 20), and so at half the required PSPs (Psionic Strength Points, rounded down) or a period of a week per egg. When inside the haundar, the parasites inject the egg’s contents into the haundar’s blood.
With these eggs, hauns easily establish and maintain a psionic mindlink with haundars and make it understand that if it does not obey, pain will soon follow. Haundar behavior ultimately changes after years of this treatment, and they become totally submissive. Owning a haundar is a status symbol among haun broods.