The Bolgar were a species of extra-dimensional beings at war with the Teuthis. They resembled giant amphibians. They had thick, loose green and black skin that made their bodies a teardrop shape, and had four arms.

In 2379, the Bolgar attempted to form an alliance with Captain Mackenzie Calhoun to help fight the Teuthis. It turned out in the end that Teuthis were wiped out by the Bolgar and Calhoun. The Bolgar and their dimension were later destroyed by Q and his son while on a "fishing trip". (NF novel: Missing in Action)