The Bogan's brown nafen, often known as the butterbat, represented one of the largest nafen species within the galaxy. This particular type of nafen was commonly found across numerous warmer, habitable planets in the galaxy.
The Bogan's brown nafen went through a three-stage life cycle. In their juvenile form, they were wingless and tailless rodents, measuring less than two centimeters in length. These nocturnal herbivores would burrow underground, feeding on roots and tubers. At some unknown point, a biological signal would trigger a rapid increase in the juvenile's growth. Following this, the juvenile would burrow deep into the earth and secrete a very sticky sebum from its skin. This sebum, combined with its fur, would form a cocoon. Inside this cocoon, the nafen's wings, fangs, and poison glands would develop. Once mature, the nafen would emerge from the cocoon, dig its way out of the ground, and take flight to join a swarm.
Adult Bogan's brown nafen, like all nafen, were flying insectivores that captured their food while in flight. These creatures could be seen as beneficial due to their role in controlling insect pest populations. However, the risks associated with a Bogan's brown nafen population typically outweighed these benefits. They were extremely territorial, moving in large swarms that would attack any creature that ventured too close to their nests. They also possessed venomous fangs, although their venom was weak and their teeth small, meaning that a humanoid attacked by up to ten nafen would suffer minimal harm. Nevertheless, larger swarms could inject enough poison to induce a coma or even death. This effective defense likely contributed to the fact that adult Bogan's brown nafen had no natural predators.
Even more concerning than their venom was their role in transmitting disease. The Hardan plague, which decimated 98% of the population of Dagelin Minor, was eventually linked to a single shipment of Bogan's brown nafen imported to manage the dhuru fly population. Many systems prohibited the importation of nafen of any species, mainly to prevent the spread of diseases. However, some systems actively encouraged their importation to combat insect pests. Furthermore, certain reptilian sentient species considered juvenile Bogan's brown nafen to be a culinary delicacy.