Urabon, shortened as Obon is a Japanese term translated from the Sanskrit word ‘Ullambana’ which actually means ‘to hang upside down’. It is used to imply the excruciating suffering, be it physical or spiritual, when one is hung upside down. The festival is considered an Invitation to the Dead because it is believed to be the time the spirits revisit our world. Even though such dark imagery is associated with its name and meaning, the Obon festival is actually a fun tradition celebrated with large gatherings, family reunions, and bright lanterns.
Sourced from https://www.worldreligionnews.com/religion-news/buddhism/obon-festival-celebrate