Conjure Greater Box

You conjure a 10 foot cube-shaped spectral box in an unoccupied space within range. The box has AC 18, 75 hitpoints and can hover.

As an action on each of you turns after casting this spell, you can move the box up to 20 feet. If you attempt to move the box into a creatures space, the creature must make a Strength saving throw. On a failed save, it takes 3d8 bludgeoning damage and gets pushed 5 feet in the direction the box was moving, the box then stops. If this movement would move the creature against a solid object, the creature becomes restrained and can use an action to attempt a Strength (Athletics) check against your spell save DC to move the box out of its space. On a succesfull save, the box stops outside of the creatures area and takes only half damage.

When you cast this spell at 4th or 5th level, you can conjure two boxes. When you cast it at 6th or 7th level, you can conjure three boxes, and the duration becomes concentration, 10 minutes. When cast at 8th or 9th level, you conjure 4 boxes and the duration becomes 1 hour. When using an action to move a box, you can move all boxes at once, freely choosing the direction for each.