Prentice (Army of Ghosts)

"Grandad Prentice" was the father of Jackie Tyler and the maternal grandfather of Rose Tyler. He was known to have smoked. He died from a heart attack in the late 1980s, but according to Jackie in 2007, came back as a friendly ghost. The 'ghost' was in fact a Cyberman, breaking through the Void as a means of travelling to Earth from 'Pete's World'. (DW: Army of Ghosts)