From TARDIS Index File, the free Doctor Who reference.
Quillam was a scientist on the prison colony world Varos who administered the (sometimes fatal) tortures in the Punishment Dome. He had a particular interest in experimenting with a machine, powered by Zyton-7, which mutated its victims according to their own unconscious wishes. He had mutilated his own face by experimenting with it and subsequently wore a mask over one eye.
Quillam subjected Peri and Areta to his machine, which began mutating them into a bird and a reptile, respectively, but the Doctor rescued them. He and the Chief Officer were later killed by deadly vines in the Punishment Dome. (DW: Vengeance on Varos)