Episode Two: The End of the World
The Moxx of Balhoon tells the Face of Boe that being trapped on the exploding Platform One is "the classic Bad Wolf scenario..."

Episode Three: The Unquiet Dead
Gwyneth the parlour maid looks into Rose's mind and sees "The Big Bad Wolf"

Episodes Four and Five: Aliens of London
A child graffiti's "Bad Wolf" onto the side of the TARDIS

Episode Six: Dalek
Eccentric billionaire Henry van Statten's has the security call sign "Bad Wolf One"

Episode Seven: The Long Game
In the year 200,000 there's a TV channel called BadwolfTV

Episode Eight: Father's Day
"Bad Wolf" is scrawled across a 1980s club poster

Episodes Nine and Ten: The Empty Child
The missile about to land on the Chula spaceship has "Schlechter Wolf" written on it

Episode Eleven: Boom Town
The nuclear power station about to destroy Cardiff is called "Blaidd Drwg".

Episode Twelve: Bad Wolf
The corporation running the GameStation is called Bad Wolf.

Episode Thirteen: The Parting of the Ways
Will all be revealed?