This case explores the aggressive mimicry behavior of "femmes fatales" fireflies--female fireflies in the genus Photuris that mimic the flash pattern of females in the genus Photinus to lure Photinus males to their death. The case features entries in an old field notebook as well as a series of handouts that the instructor presents to students for analysis and in-class discussion. Here, the author discusses fireflies and their characteristics, and presents a homework assignment related to the case study that was given to the students.