Curse of the Raven Queen

A portal opens to the Shadowfell on a point you choose within range. For one minute, all creatures within a 20 foot sphere are surrounded by the ghosts who haunt the Fortress of Memories. Each creature who starts their turn in this sphere must make a Constitution saving throw or take 4d6 necrotic damage. Each creature who ends their turn inside the sphere must make a Wisdom saving throw or take 4d6 psychic damage. The sphere counts as difficult terrain, and creatures inside the sphere are unable to see outside of it.