Conjure Ocean

You create a chaotic cloud of butterflies in a 20-foot-radius
sphere centered on a point you choose within range. The
area is heavily obscured, and resting smoke or fog in the
area is dispersed.

Creatures of your choice in the area when you cast this
spell ignore the following effects. For the duration, the
affected area is difficult terrain. When a creature attempts
to leave the spell’s area, it must make a Strength saving
throw. On a failed save, it is pulled back to an unoccupied
space closest to the center of the sphere.