The Ring of Shooting Stars has the following feature (emphasis mine):
Ball Lightning.
You can expend 2 charges as an action to create one to four 3-foot-diameter spheres of lightning. The more spheres you create, the less powerful each sphere is individually.
Each sphere appears in an unoccupied space you can see within 120 feet of you. The spheres last as long as you concentrate (as if concentrating on a spell), up to 1 minute. Each sphere sheds dim light in a 30-foot radius.
As a bonus action, you can move each sphere up to 30 feet, but no farther than 120 feet away from you. When a creature other than you comes within 5 feet of a sphere, the sphere discharges lightning at that creature and disappears. That creature must make a DC 15 Dexterity saving throw. On a failed save, the creature takes lightning damage based on the number of spheres you created. (4 spheres = 2d4, 3 spheres = 2d6, 2 spheres = 5d4, 1 sphere = 4d12)
Does this mean that the sphere discharges lightning whether you move it within 5 feet of a creature or whether a creature moves within 5 feet of it?
What happens if you move it within 5 feet of multiple creatures at once (or multiple creatures move within 5 feet of it at once)?