Elemental Hybrid. The treant is also an elemental.

False Appearance. While the treant remains motionless, it is indistinguishable from a normal burning tree.

Illumination. The treant sheds bright light in a 40-foot radius and dim light for an additional 40 feet.

Siege Monster. The treant deals double damage to objects and structures.

Tinder Aura. Other plants within 30 feet of the treant have vulnerability to fire damage.

Water Susceptibility. For every 5 feet the treant moves in water, or for every gallon of water splashed on it, it takes 1 cold damage.

Wildfire Aura. At the start of each of the treant's turns, each creature within 5 feet of it takes 10 (3d6) fire damage, and flammable objects in the aura that aren't being worn or carried ignite. A creature that touches the treant or hits it with a melee attack while within 5 feet of it takes 10 (3d6) fire damage. Any flammable object that the treant touches (including those it walks on) ignites instantly if it isn’t being worn or carried.

Multiattack. The treant makes two slam attacks.

Slam. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 16 (3d6 + 6) bludgeoning damage plus 5 (1d10) fire damage.

Rock. Ranged Weapon Attack: +11 to hit, range 60/180 ft., one target. Hit: 28 (4d10 + 6) bludgeoning damage, and the target and each other creature within 5 feet of it also takes 10 (3d6) fire damage.

Flame Jet. Ranged Spell Attack: +9 to hit, range 120 ft., one target. Hit: 22 (4d10) fire damage. If the target is a creature or a flammable object, it ignites. Until a creature takes an action to douse the fire, the target takes 5 (1d10) fire damage at the start of each of its turns.

Immolate Trees (1/Day). The treant magically animates one or two trees it can see within 60 feet of it, lighting them ablaze in the process. These trees have the same statistics as a wildfire treant, except they have Intelligence and Charisma scores of 1, they can't speak, they have no Tinder Aura, and they have only the Slam action option. An animated tree acts as an ally of the treant. The tree remains animate for 1 day or until it dies; until the treant dies or is more than 120 feet from the tree; or until the treant takes a bonus action to turn it back into an inanimate tree. The tree then burns to ashes.