Cephalonikin, formerly known as IMC-2 (Imulsion Mutagenic Compound 2), is a small-molecule chemical mutagen that binds to the minor groove of deoxyribonucleic acid (DNA) polymers in GC-enriched regions. It is a natural product found in imulsion extract that was shown to at least in part mediate the neuropsychological phenotype induced by exposure to high concentrations of imulsion extract.