Mordenkainen's Lost Notebook
6-level Transmutation
All windows, doors, or other forms of egress in a 40-
foot cube instantly slam shut and are secured with an
arcane lock. Each opening is secured with its own arcane
lock, which must be dispelled separately.
At higher levels: At higher levels: When you cast this spell using a spell
slot of 7th level or higher, the size of the cube increases by
10 feet for each slot level above 6th.