Comet Puzzle

You summon a hollow sphere of rock 10 feet in diameter within range, any creature inside of the radius when the spell is cast is stuck inside. Inside of the rock are 4 tiny illusory cubes in locations determined by the caster. A creature can use an action to make an intelligence check with a DC of your spell save DC and move a cube of their choice that they can see up to 20 feet in any direction. The cubes cannot be physically touched, but cannot leave the boundaries of the rock. If all 4 illusory cubes are placed over each other, the spell is dispelled and the rock turns into dust.

At Higher Levels: When cast with a spell slot of 7th level or higher, the number of cubes in the rock increases by 1.