NULL-003 Or "The Deadlight" are dark figures with an angler bulb made from unknown origin. Speaking of origins, origins of Deadlights are unknown, as the earliest documentation have next to no information. However, here is what IS known. 

Deadlights use light to their advantage, they use it to lure prey in dark environments. While it is human nature to try to seek light in dark areas. Keep your distance. Don't trust light sources unless you can hear someone talking. Deadlights are deaf, so if you see light make sure to yell. If there's no response, run for your life.