All Monsters Attack (1969)

Ichiro is a highly imaginative, but lonely, boy growing up in urbanized and industrial district of Kawasaki. Every day he comes home to the empty apartment he shares with his railroad worker father and his restaurant hostess mother, his only friends being a toy maker name Shinpei Inami and a girl named Sachicko. Ichiro finds himself the victim of a gang kids led by a bully nicknamed Gabara. To escape his loneliness, Ichiro turns to escapist fantasies and imagines himself on Monster Island and befriending Minillia, the son of Godzilla. Through his friendship with Minilla, Ichiro confronts his solitude and face his fears.