Jellyfish Eyes (2013)

Description:

An elementary school student named Masashi finds flat cardboard boxes at a home in which he just moved in. A strange creature like jellyfish comes from the cardboard. Masashi names the strange, but cute creature "Kurage Bo" and they become friends. Masashi places Kurage Bo in a bag and takes the creature with him to school his new school. The other students and adults can not see Kurage Bo.