Vampiric Circle

You summon an aura of draining energy centered around yourself emanating 20 feet in every direction. Creatures caught in the aura are physically drained while you turn their strength into a deadly force that increases the effectiveness of your necromancy spells. Creatures that start their turn in the radius or move into the radius for the first time on their turn must make a Constitution saving throw or have their speed reduced by half as well their strength and constitution scores reduced by 1d4 each until the end of the spell. Undead creatures automatically succeed on this saving throw. The next spell you cast that deals necrotic damage during the spell’s duration deals an extra 1d6 damage for each creature caught in radius that failed its saving throw.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher; the increases damage of your spell increases by 1d6 for each slot level above 3rd. If you cast this spell at 6th level or higher; the reduction of creature’s strength and constitution increases by 1d4 for each slot level above 5th.