Zzagnar the All-Conquering was a self-written story that attempted to mind control the Earth through a narrative virus of itself given away for free.
In 2015, the Eleventh Doctor used a comic book and the TARDIS's telepathic circuits to channel the living story into a host body—made of waste matter from ARC — which broke the mind control.
Zzagnar later started writing normal comic books. His Zz-Men series was quite popular. (COMIC: Give Free or Die)