GoGo Monster(1998)

GOGO Monster

Third grader Yuki Tachibana lives in two worlds. In one world, he is a loner ridiculed by his classmates and reprimanded by his teachers for telling stories of supernatural beings that only he can see. In the other world, the supernatural beings vie for power with malevolent spirits who bring chaos into the school, the students' lives, and nature itself.

(Source: Viz Media)