Going by Google translation, this is apparently some sort of composting device that also doubles as a Yukkuri repellent, as the constant stench of death is overwhelming.
Baby yukkuri will be born regularly. The damage from the fall into the box won't be fatal. Inside they will feel despair from being unable to find their parents, starvation, and tortured by the death stench of their siblings who died earlier. All of these made the death stench from their corpse much stronger. Take the accessories from the dead baby yukkuri as yu-repellant. The corpse will be infested by insects, so it's recommended to return them to their parents.
marichanaga is fast becoming my favourite artist with their little shorts. The details are always a treat. I like how in addition to being composting machines, they have garbage on their heads.