Banksy was a human graffiti artist.
Carla Langer told Sarah Jane Smith that Clyde Langer wanted to be the new Banksy. (TV: The Mark of the Berserker)
Amy Pond told the Eleventh Doctor that Banksy and Damien Hirst put out statements that the Shakri cubes had nothing to do with them. (TV: The Power of Three)
The Eleventh Doctor called a young man who had used a spraying can in Rokhandi World "Banksy Junior". (COMIC: The Friendly Place)
While in Montgomery, Alabama in 1955, the Thirteenth Doctor suggested to her companions that she was Banksy. (TV: Rosa)