RENTAGHOST

1976 saw the start of one of the most horrific shows ever on the BBC. It tells the tale of Fred Mumford, a man drowned at sea, whose corpse still lies undiscovered in the depths. His ghost walks the Earth and is able to visit his parents. Comedy ensues as he has to hide from them the fact that he is in fact the shade of their dead son.
Imagine their horror if his body is ever discovered and they realise that they were visited by him long after his death.
Rentaghost is quite dark if you think about it.