Vortex of Decay

A 40-foot diameter portal into the River Styx erupts centered on a point you choose within range. An ethereal vortex of decay seeps out of the portal, the air inside the vortex is filled with the smell and sounds of death eternal. Each creature within the sphere must make a Wisdom saving throw or take 2d8 psychic damage and frightened.  The vortex remains for the spell’s duration. The vortex's space is difficult terrain.

Until the spell ends, you can use a bonus action on each of your turns to cause a tendril of eldritch energy to leap from the center of the vortex toward one creature you choose within 60 feet. The creature makes a Dexterity Check, and has disadvantage if it is within the vortex or frightened. On a fail, the target takes 4d6 necrotic damage and is grappled, being pulled 10 feet towards the center. On pass, the creature takes the damage but is not grappled or pulled. On each of the creature's turns, it repeats the Dexterity Check or remains grappled. The number of total creatures that can be grappled is equal to your spell casting modifier. 

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases for each of its effects by 1d6 for each slot level above 4th.