Theatre of the Mind

When you cast this spell a 300 foot radius sphere erupts from you, expanding space in your location. Yourself and any creatures within range remain, but everything else is pushed out, as if the new space had always been there. Within the sphere the atmosphere, land, and structures within are determined by the material used in the casting. Everything created within the sphere is real, but anything created taken from the sphere will vanish the moment it leaves the range of the spell. Any material which would appear to harm or impede, such as snow, fire, or poison, is purely cosmetic and confers neither benefit or harm to any creature, unless that material is physically present on the material used for in casting this spell in which case the DM determines what effects may occur. When this spell's duration is over, the space contracts back to normal and everything created within it vanishes. When this space is created and when it ends, creatures and objects within the area are moved to the closest unoccupied space they can safely reside. If at any point you leave the area of the spell, the spell immediately ends. 

At Higher Levels: Every spell slot after 7th used to cast this spell doubles the range of the sphere.