False Appearance. While Gulthias Tree remains motionless, it is indistinguishable from a dead tree.
Siege Monster. Gulthias Tree deals double damage to objects and structures.
Summon Blights (Lair Action). On initiative count 20 (losing initiative ties), the Gulthias Tree takes a lair action to spawn 1d4 Twig Blights with 1 HP.
Multiattack. The Gulthias Tree makes 2 attacks with its branches or grasping roots. If it has a target grappled, Gulthias Tree can also make a bite attack against that target as a bonus action.
Branch. Melee Weapon Attack: +5 to hit, reach 15 ft., one target. Hit: 9 (2d6+2) bludgeoning damage.
Grasping Root. Melee Weapon Attack: +5 to hit, reach 15 ft., one target. Hit: 5 (1d6+2) bludgeoning damage. The target is grappled (escape DC 15). Until this grapple ends, the target is restrained. The roots have AC 16 and can be severed by dealing 6 slashing damage or more to it at once. Cutting the root doesn't hurt the Gulthias Tree but ends the grapple.
Bite: Melee Weapon Attack: +5 to hit, reach 5ft., one target. Hit: 9 (2d6+2) piercing damage.
Frightful Presence. Red blood oozes from Gulthias Tree's pores. Each creature that is within 30 ft. of Gulthias Tree must succeed one a DC 15 Wisdom saving throw or become Frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to Gulthias Tree's Frightful Presence for the next 24 hours.
Poison Breath (Recharge 5-6). Gulthias Tree exhales poisonous gas in a 15-foot cone. Each creature in that area must make a DC 15 Constitution saving throw, taking 21 (6d6) poison damage on a failed save, or half as much damage on a successful one.
The Gulthias Tree can take 2 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. The Gulthias Tree regains spent legendary actions at the start of its turn.
Roots. Gulthias Tree makes one Grasping Root attack.