Cube

5th-level conjuration (wizard)

Casting Time: 1 action
Range: 120 feet
Components: V,S
Duration: Concentration, up to 1 minute

A perfect 10-foot cube appears in an unoccupied space of your choice within range and lasts for the duration. This space can be in midair, if you so desire.

The cube is black and completely non-reflective. Any creature that ends its turn within 5 feet of the cube must make an Intelligence saving throw, taking 5d6 psychic damage on a failed save, or half as much damage on a successful one.

As a bonus action, you can move the cube up to 10 feet in any direction, so long as the space it will end on is within your line of sight. The cube cannot be made to pass through other creatures, although a creature may choose to pass through the cube on its own turn.

Entering the space the cube occupies forces a creature to make an Intelligence saving throw. The creature takes 5d6 psychic damage on a failed save, or half as much damage on a successful one. This damage does not prevent the creature from taking additional damage if it ends its turn within 5 feet of the cube.

A construct must succeed on a Wisdom saving throw when attempting to pass through the cube. On a failure, it cannot pass through the cube. On a success, it may pass through the cube (and will then immediately need to make an Intelligence saving throw as normal, unless it is immune to psychic damage).