Origami balls are called “Kusu-Dama”.
They were introduced into Japan in the Heian period from China (The Heian era is from794 a.d. to 1192 a.d.
Originally they were made of herb medicines put into brocade and decorated with artificial flowers into an ornamental scented ball. They were hung on a reed screen or a pillar to give a wide berth to the evil spirit or as a charm and bringer of good luck.
More recently, the Kusu-Dama is made from Origami paper, and the shape of all polyhedrons. So, it is called "unit origami".
Many Japanese people enjoy making and decorating the Kusu-Dama. They are still developing today.