Cogs of Mechanus

You summon 3 floating cogs, each in an unoccupied space within range. They each occupy a 5-foot cube. When this happens, you may choose any number of creatures to be immune to this spell. When a creature enters a cog’s space, they must succeed on a passive Strength saving throw or take exactly 2 bludgeoning damage and be pushed 5 feet away from the cog.