I.J. Good coined the term intelligence explosion

The term “intelligence explosion” was introduced by the mathematician Irving John Good in his 1965 paper “Speculations Concerning the First Ultraintelligent Machine.” Good wrote that because an ultraintelligent machine “could design even better machines; there would then unquestionably be an ‘intelligence explosion,’ and the intelligence of man would be left far behind.” The phrase has been the standard name for the runaway self-improvement scenario ever since.