"tonka_boy" was the username of a reader of Mickey Smith's conspiracy website Who is Doctor Who? by 2006.
Biography
After the crash of the Slitheen craft in Central London, (TV: Aliens of London) tonka_boy drew the spaceship and sent it to Mx — the webmaster of Who is Doctor Who? — who posted it on his website. (PROSE: Alien landing confirmed)
Behind the scenes
Although similar in nature to the user-created characters in Alien landing confirmed, tonka_boy was included in the main text of the story and therefore was created by the BBC webteam.