Ancient Treant

Speak with Beasts and Plants. The treant can communicate with beasts and plants as if they shared a language.

Magic Resistance. The treant has Advantage on saving throws against spells and other magical effects.

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

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

Multiattack. The treant makes two slam attacks, any of which it can replace by either two Verdant Wisp attacks or one use of Spellcasting.

Slam. Melee Attack Roll : +12, reach 10 ft. Hit : 26 (3d12 + 7) Bludgeoning damage and 16 (3d10) Force damage.

Verdant Wisp. Ranged Attack Roll : +12, range 180 ft. Hit : 16 (3d10) Radiant damage.

Spellcasting. The treant casts one of the following spells, using Wisdom as the spellcasting ability (spell save DC 20), requiring no material components:

At will : Animal Friendship, Animal Messenger, Beast Sense, Commune With Nature, Create or Destroy Water (level 3 version), Detect Poison and Disease, Detect Magic, Druidcraft, Entangle, Lesser Restoration, Locate Animals and Plants

1/day each : Awaken, Cure Wounds (level 3 version), Find The Path, Move Earth, Plant Growth, Transport via Plants

Animate Trees (1/Day). The treant magically animates one or two trees it can see within 60 feet of it. These trees have the same statistics as the ancient 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 ally of the ancient treant. The tree remains animate for 1 day or until it dies; until the ancient treant dies or is more than 120 feet from the tree; or until the ancient treant takes a bonus action to turn it back into an inanimate tree. The tree then takes root if possible.