Xykon's Occlude Light

A magical spherical barrier appears with a 15 foot radius centered on a point of space immediately below the caster. This barrier blocks all light from the outside, making the sphere appear completely dark from without. Any lights created within emit dim light instead of bright and any dim light they would otherwise emit is not created. Lights within the barrier are invisible to the outside. Any creature within the radius is immune to radiant damage from outside the effect, and any radiant damage sourced from within the effect deals half damage. All living creatures within the sphere are vulnerable to necrotic damage. The barrier prevents light from passing through, but not material or creatures. While the sphere of darkness is centered on the caster at the time of casting, it does not move with them if they move, nor can it be attached to a surface and then moved.