Luminescence in Amphipholis squamata has only been observed from chemically stimulated individuals, and the present laboratory study assessed the natural expression of luminescence following interaction with co-occurring organisms. The luminescence occurred only in response to (mechanical) stimulus and ranged from weak to intense reaction depending on the contact organism. Only crustaceans triggered an intense luminescence. Brachial autotomy also occurred after prolonged interaction and the luminescence continued only from the autotomized arm, which could lure the crustacean. The study showed that A. squamata luminescence could be naturally stimulated by co-occurring organisms, and the light produced sufficiently intense to be detected.