Cursed Ground

You curse a patch of ground within range, causing the area in a 10 ft. radius Sphere around it to become Difficult Terrain for the duration. A creature that starts it's turn on this ground must succeed on a Constitution saving throw or take 2d6 Necrotic damage and have Disadvantage on attack rolls until the end of it's next turn.

Using a Higher-Level Spell Slot. The Necrotic damage increases by 1d6 per level of spell slot above 2.