Klineman Halpen was the Chief Executive of Ood Operations, a job that had been passed down from his Grandfather, to his Father, and eventually, himself. At the age of six he was taken to the Ood Sphere and saw the Giant Ood Brain within. He had his own personal Ood that looked after him named Sigma. The stress associated with running Ood Operations caused him to have significant hairloss in five years, presumably when he assumed control of the business, and so was dosed with hair tonic by Sigma. When the Ood began getting infected with Red Eye, Halpen arrived on Ood Sphere to oversee it's eradication and establish control. When the entire Ood "livestock" were infected with this mysterious disease, Halpen ordered the gassing of all affected Ood, and then intended to destroy the Giant Ood Brain in order to contain the Red Eye and kill the Ood.
Ood Sigma led the Doctor and Donna Noble to the Ood Brain for the final confrontation. When his lead scientist Dr. Ryder revealed that he was a Friend of the Ood and had spent the last ten years infiltrating the Company to lower the Psychic barrier surrounding the Ood Brain, Halpen threw him into it, devouring him. Halpen, sensing defeat and suffering from intense headaches, Sigma revealed that he had used the Hair Tonic liquid to dose Halpen with Ood graft suspended in a biological compound that was turning him into an Ood as punishment for his attitude towards his kind. Sigma then declared he would look after Halpen. (DW: Planet of the Ood)