Strontium Dog is a British comic series created by John Wagner and Carlos Ezquerra, first appearing in the anthology magazine 2000 AD in 1978. The story follows Johnny Alpha, a mutant bounty hunter in a post-apocalyptic future, as he tracks down criminals across the galaxy. The series combines elements of science fiction, action, and dark humor. The title "Strontium Dog" refers to the effects of strontium-90, a radioactive isotope, which causes mutations in humans. The series explores themes of prejudice, survival, and morality, often highlighting the struggles faced by mutants in a society that fears them.