Blaze of Elementals

Water Susceptibility. The blaze has vulnerability to bludgeoning damage from attacks that create or manipulate water. If the blaze starts its turn fully immersed in water, or immerses itself for the first time on a turn, it takes 39 (6d12) cold damage, or half as much if only partially submerged. When one or more gallons of water are splashed onto the blaze, it takes 3 (1d6) cold damage.

Death Throes. When the blaze drops to 87, 43, and 0 hit points, it releases an explosion of flame. All creatures within 30 ft. of the blaze when it reaches each threshold must make a DC 16 Dexterity saving throw, taking 19 (3d12) fire damage on a failure, or half as much on a success. The blaze does not explode in this way if cold damage brings its hit points to the threshold.

Elemental Swarm. The blaze can occupy another creature's space and vice versa, and can move through a space as narrow as 1 inch wide without squeezing. It cannot have its speed reduced, or be forced to move without using its movement, action, or reaction. The blaze cannot regain hit points, nor can it gain temporary hit points.

Illumination. The blaze sheds bright light in a 60 ft. radius, and dim light for an additional 60 ft. 

Raging Inferno. If a creature starts its turn in the blaze's space, or hits it with a melee attack while within 10 ft. of it, the creature takes 9 (2d8) fire damage.

Multiattack. The blaze can make three attacks. If it is below half its maximum hit points, it makes two instead.

Scorch. Melee Weapon Attack: +9 to hit, reach 0 ft., all targets within the blaze's space. Hit: 9 (1d12+3) fire damage. If the target is a creature or a flammable object, it catches on fire. Until a creature uses an action to douse the flames, the target takes 6 (1d12) fire damage at the start of each of its turns.

Fire Bolt. Ranged Spell Attack: +9 to hit, range 150 ft., one target. Hit: 13 (2d12+3) fire damage.