- You may be looking for the Tharil.
Laszlo was ambushed by pig slaves while backstage in the theatre. They took him to the Daleks to be changed into one of them. He escaped the Cult of Skaro before the process could be completed and therefore, unlike the other slaves, retained some of his human features and was capable of intelligible speech; he lacked a pudgy face and retained his hair. (TV: Daleks in Manhattan)
He helped the Tenth Doctor fight against the Daleks, but eventually found it hard to even stand as his body deteriorated; pig slaves had a limited lifespan and Laszlo was dying. However, the Doctor renewed his lifespan to that of a human, and Laszlo went on to live at Hooverville with Tallulah still his girl, despite the fact that the process could not be reversed. (TV: Evolution of the Daleks)
Behind the scenes
Writer Helen Raynor originally intended for Laszlo to die. Executive producer Russell T Davies, who felt that the development was too depressing for the Doctor Who ethos, asked her to change this development. (DWMSE 17)