Gaze of Hadar

You open a gateway to the dark between the stars, a region infested with unknown horrors. An eye, made out of liquid shadow and darkness, gazes upon a 30-feet cone and burns the mind of everything in it's path. Each creature in a 30-foot cone must make a Wisdom saving throw. A creature takes 12d12 fire damage on a failed save, or half as much damage on a successful one.

Everyone inside the cone can hear whispers and the slurping of tentacles. Any creature killed by the fire damage turns into ash and is being absorbed by the eye, magical items are left behind.