Barrier of Retention (EFA - B)

You create a one-way, invisible barrier around an 20-foot-radius spherical area within range you can see. Creatures entering the sphere suffer no ill effect, but they can’t leave the sphere’s area unless they succeed on a Constitution saving throw. You can pass through the barrier either way freely.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the radius increases by 10 feet for each slot level above 5th.