Mt.Fuji is a famous volcano in Japan in the real world. Despite it's name it's a volcano. Cousin Fujio is usually found around it. It's possible his head is Mt.Fuji. Evidence is that when Fujio wears his Mt.Fuji only clouds and the sun appear. His name is also evidence and quotes are made. But Fujio is always a seperate item than Mt.Fuji. There are also Mt.Fuji clouds that surround the volcano just to give it that high up feeling. The katamari has to be built up really well to roll up Mt.Fuji. It like other famous landmarks sometimes change spots in the games.