Tempest Spirit

The spirit can move through other creatures and objects as if they were difficult terrain. The spirit takes 5 (1d10) force damage if it ends its turn inside an object.

If the spirit fails a saving throw, it can choose to succeed instead.

The spirit makes two Lightning Fist or Hailstone attacks in any combination.

Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 25 (4d8 + 7) lightning damage.

Ranged Weapon Attack: +12 to hit, range 90/180 ft., one target. Hit: 17 (3d6 + 7) bludgeoning damage plus 7 (2d6) cold damage.

The spirit hurls a magical lightning bolt in a 120-foot line that is 10 feet wide. Each creature in that area must make a DC 18 Dexterity saving throw, taking 27 (6d8) lightning damage plus 16 (3d10) necrotic damage on a failed save, or half as much damage on a successful one. On a success or failure, an affected creature's hit point maximum is reduced by an amount equal to the necrotic damage taken. This reduction lasts until the creature finishes a long rest. The creature dies if its hit point maximum is reduced to 0.

The spirit conjures a hailstorm in a 20-foot-radius, 40-foot-high cylinder centered on a point it can see within 120 feet of itself. Each creature in that area must make a DC 17 Dexterity saving throw. On a failed save, a creature takes 10 (3d6) bludgeoning damage plus 10 (3d6) cold damage and has the prone condition. On a successful save, a creature takes half as much damage only.