False Appearance. While the Corrupted Treant remains motionless, it is indistinguishable from a normal leafless tree.
Siege Monster. The Corrupted Treant deals double damage to objects and structures.
Sap Life. The Corrupted Treant saps the life out of all plants it comes in contact with. In doing so it can heal by 2d4 hp every other round at the start of its turn without expending any action or bonus action. Plant-life around it withers and fades. Animated plants touched by this creature will lose 20 hp and 5 movement speed at the start of their turn for every turn they are in physical contact with the Corrupted Treant. The Corrupted Treant gains an additional 1d20 hp (every other round at the start of its turn) for each animated plant it has corrupted that is within a 15 foot radius of it.
Corrupt Nature. If Corrupted Treant uses rake on an animated plant and that plant fails a constitution saving throw, they become corrupted instead of poisoned (known as lesser corrupt treants). While corrupted they are loyal to the original Corrupted Treant and will attack everything uncorrupt. They now also gain the "rake" attack and "corrupt nature" ability. However, they will also continue to lose health if they are within a 15 foot radius centered around the Corrupted Treant (but not movement speed) as the Corrupted Treant saps their life, despite not being in physical contact with it. They also gain a disadvantage on constitution saving throws. Their stats do not change. Animated plants they corrupt are affected by the Corrupted Treeant's "sap life" while in a 15 foot radius of the Corrupted Treant.
Thick Bark. The Corrupted Treant has resistance to fire spells from a 4th level spell slot or lower.
Multiattack. The Corrupted Treant makes two slam attacks.
Slam. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: (3d6 + 6) bludgeoning damage.
Rake. Melee Weapon Attack: +10 to hit, reach 10ft., two targets only if they are adjacent to each other. Hit: (2d8+6) slashing damage. 1d4 poison damage unless target succeeds a constitution saving throw.
Rock. Ranged Weapon Attack: +10 to hit, range 60/180 ft., one target. Hit: (4d10 + 6) bludgeoning damage.
Animate Trees (1/Day). The Corrupted Treant magically animates one or two trees it can see within 60 feet of it. These trees have the same statistics as a treant, except they have Intelligence and Charisma scores of 1, they can't speak, and they have only the Slam action option. An animated tree acts as an enemy of the Corrupted Treant. The tree remains animate for 1 day or until it dies; until the Corrupted Treant dies or is more than 120 feet from the tree; or until the Corrupted Treant takes a bonus action to turn it back into an inanimate tree. The tree then takes root if possible.
Unbridled Rage. The Corrupted Treant lets out a screech and goes on "all-fours." All uncorrupt entities near it (in a 15 foot radius centered on the Corrupted Treeant) must succeed a wisdom check or be frightened for 18 seconds. It charges forward towards the nearest "enemy" with twice its movement speed, dealing 5d8+6 bludgeoning damage to whoever is in its path. It only does this rarely, once when it is below half-health, and with no limit once it has reached 20 hp or lower. After use its movement speed is reduced to 5 feet until the end of its next turn.
Entangling Roots. The Corrupted Treeant causes roots to sprout up to 30 feet away from it, filling a 10 foot radius. Anyone within the center of the radius must succeed a strength saving throw or be immobilized until a successful save or check. Anyone within the outer areas of the radius must succeed a dexterity saving throw or be subject to the same conditions. The roots then become difficult terrain. The Corrupted Treeant can only perform this action 3 times.