He has a head which somewhat resembles a carnivorous bovine or a dragon with pairs of horns and whiskers. His whole body is covered with black or navy blue colored hairs.
While Kuro-Kaibutsu didn't appear directly, Qi showed illusions as a last stand when his castle was on fire, and one of these illusions resembled Kuro-Kaibutsu.
Kuro-Kaibutsu appeared in the third movie based on the third anime adaptation, GeGeGe no Kitarō: Saikyō Yōkai Gundan! Nippon Jōriku!!
In the tale Mizuki introduced within his book, it is rather unclear which of the three monsters the protagonist encountered was the actual Kuro-Kaibutsu as all those were described to be black in coloration. The three monsters, the two in the left and the one with long hairs and tongue fought each other for the protagonist and the man was able to escape thanks to the battle.