20 Greatest Moments In Modern Doctor Who
17. Constantine Transforms (The Empty Child)
The Unquiet Dead had already established that 21st century Doctor Who wasn't afraid to terrify its young audience, but The Empty Child picked up that baton and set out to traumatise a generation of kids with the transformation of Doctor Constantine into a gas mask zombie.
It's an incredible scene, from the melancholic exchange between the two doctors about war, grief, and loss, to Constantine's desperate questioning of "Are you my Mummy?"
It's the fact that writer Steven Moffat and actor Richard Wilson imbue so much personality into Constantine in such a short space of time that makes the horrifying transformation so utterly chilling – and one that young eyes back in 2005 have not forgotten to this day!