Your basic three-headed dragon, with the head of a dog, a gryphon, and a man. “Speaketh with a high and comely voice,” which is not immediately intuitive.
Bune is, for the most part, a goetic “stub entry” without a lot of color. However, his powers are interesting. There’s some of the usual stuff, (giveth riches, maketh one wise and eloquent, gives true answers unto demands). But regarding his control over the dead, he can make the dead change their places, and bring demons and devils together to assemble at graves. He may be a sort of gatekeeper between the land of the dead and the land of the living.
The influential demonologist Dr. Rudd says that Bune’s name is in fact Bim. If that’s the case, the amusingly awful 1980 disco-apocalypse movie “The Apple” may give us an insight into what Bune’s human form and his worship looks like.