Members of this species were of purple colour and had amorphous, vaguely humanoid shapes with glistening tubular limbs and with dimples in place of eyes, nostrils and mouth in their ill-formed heads, set on barely discernible necks. They smelled like nail varnish. Their blood was pale blue and glutinous.
Their bodies could not withstand significant exertion. Instead, they developed a technology allowing them to appropriate nearby bodies of other species and energy from nearby energy sources. Their ships could travel through space and time by appropriating space at the intended destination.
Their body-controlling technology was humane in that the host was not aware of being controlled and later had no memory of the actions performed under control. However, if the body of the controlling entity was killed while it was inside somebody else's body, the owner of the host body died too.
The controls of their equipment were partially telepathic.
The pilot was killed by Garry Fletcher. Shortly after their arrival, the other four crew members from the expedition were killed by Fletcher and his friend Mike who used a lump hammer and crowbar respectively. For six months their bodies were kept in a back room of the industrial estate. Then the Coal Hill defenders put them into Fletcher's car to be found by the police. The bodies were later removed from police evidence by a team from UNIT. (PROSE: Joyride)