In both senses of the word: this thing was huge -- body length 3.5 cm (1-3/8") -- and females of this genus, Photuris, lure males of other species by imitating that species's flash patterns and then kill and eat them. Found at moth bait, observed flashing while crawling up the tree.
Small winged black bug
Lampyridae is a family of insects in the beetle order Coleoptera. They are winged beetles, and commonly called fireflies or lightning bugs for their conspicuous crepuscular use of bioluminescence to attract mates or prey. Fireflies produce a "cold light", with no infrared or ultraviolet frequencies. This chemically produced light from the lower abdomen may be yellow, green, or pale red, with wavelengths from 510 to 670 nanometers.