Native to the Core Worlds planet of Corulag, bulfusi were dark-furred, muscular, oily mammals with long whiskers and double-lidded eyes; those features gave them otter-like aspects, although the creatures were sleek and bat-like in shape. Bulfusi were intensely unpleasant-smelling when wet which, considering their habitat and lifestyle, was often. Bulfus pups clung to the upper dorsals of their parent until they reached five months of age and learned to fly.
Bulfusi were nocturnal predators that lived in muddy waterside burrows and were capable of hunting in water or in the air, in both cases descending to snatch small prey from undergrowth. While largely placid towards Human-sized beings, bulfusi were highly protective of their offspring and would fiercely defend them if disturbed or threatened. A full-speed dive-bombing attack from a bulfus was capable of knocking a Wookiee off its feet. Despite such behavior and a formidable bite, bulfusi could be domesticated with effort, but they made poor pets due to their large size and appetite. Even so, some of Corulag's inhabitants trained bulfusi as guard animals and entertainers.
Bulfusi were first mentioned in the sourcebook Coruscant and the Core Worlds, which was published by Wizards of the Coast in 2003 for use with the Star Wars Roleplaying Game.