Onigawara (from the Japanese word oni, meaning “ogre”) are monster heads sometimes found on the roofs of Japanese buildings. They are similar to what we typically call “grotesques” – decorative creatures with symbolic, religious, or ideological rather than practical function. The onigawara I’ve seen are generally closer to relief-carvings than other types of grotesque, and accordingly, I haven’t found any indication that they ever serve as gargoyles. Such a function would likely necessitate three-dimensionality. I greatly enjoy their highly-expressive aesthetic, and though they’re not quite gargoyles, I feel that they should be considered as related creatures.