Entity 415, also known as Bacteria, Howler or Lifeform is creature or possibly a group of creatures that inhabit(s) the Backrooms and prey(s) on victims that have blackfound themselves in their presence. They're extremely dangerous toward humans and has been cause for concern among the Major Explorer Group, the Backrooms Nonaligned Trade Group and other organizations in the Backrooms in their mission studying the dimension, Bacterias/Howlers/Lifeforms are one of the creatures that are common.