You reshape the terrain in a 30-foot-radius area you can see within range into a phantasmal, nightmarish landscape. Creatures in the area perceive the terrain as unnavigable or threatening, such as shifting sands, thorny undergrowth, or unstable cliffs. The illusion is semi-tangible, imposing disadvantage on Dexterity saving throws and halving movement speed. Creatures that interact with the terrain can make an Intelligence (Investigation) check against your spell save DC to see through the illusion, but it remains difficult terrain regardless.