Chittering Swarm

 Protective spirits flit around you in a 30-foot Emanation for the duration. They appear abstract as Fey insectoids and vengeful Fey spirits who wish to rip and shred them apart.

When you cast this spell, you can designate creatures to be unaffected by it. Any other creature’s Speed is halved in the Emanation, and whenever the Emanation enters a creature’s space and whenever a creature enters the Emanation or ends its turn there, the creature must make a Wisdom saving throw. On a failed save, the creature takes 4d8 Necrotic damage. On a successful save, the creature takes half as much damage. A creature makes this save only once per turn.

Using a Higher-Level Spell Slot. The damage increases by 1d8 for each spell slot level above 3.