After looking into the Heart of the TARDIS, the Time Vortex itself filled Rose Tyler, who then temporarily became the Bad Wolf entity. She scattered the two words throughout time as a sign to herself that she was linked to the Doctor, creating a looped ontological paradox. Bad Wolf letters are embroidered onto the front of the wallet. Made of 100% Genuine Leather. Measures about 8-inches long x 4-inches wide.