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.

Boon of Roots. At the end of Yiggis' turn, if he didn't move on his turn, he regains 10 hit points and has advantage on ability checks and saving throws to resist being moved or knocked Prone. Yiggis cannot gain the benefit of this ability while at 0 hit points.

The First Guardian. While conscious and within the Grove, Yiggis is permanently under the effects of the spell Guardian of Nature (Primal Beast).

Multiattack. Yiggis makes two slam attacks.

Slam. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 17 (3d6 + 7) bludgeoning damage plus 3 (1d6) force damage.

Rock. Ranged Weapon Attack: +12 to hit, range 60/240 ft., one target. Hit: 29 (4d10 + 7) bludgeoning damage.

Leaf Storm (1/Day). Yiggis releases a storm of his leaves in a 30-foot radius sphere centered on him that moves with him. When a creature starts its turn within the sphere, or moves within it for the first time on its turn, it must make a DC 18 Dexterity saving throw. It takes 22 (4d10) slashing damage on a failure, or half as much damage on a success. The entire sphere counts as difficult terrain and heavily obscured, and lasts for 1 minute or until Yiggis loses concentration on it (like a spell). Yiggis and his allies are immune to its effects.

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 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 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 takes root if possible.

Nature's Balm (5/Day). Yiggis touches a creature within 5 feet of him and allows them spend 3 hit dice as if they had finished a short rest.