Warden of the Root

Legendary Resistance. (2/Day) If the Warden fails a saving throw, it can choose to succeed instead.

Rootstride. The Warden can move through difficult terrain made of earth or plants without penalty and does not provoke opportunity attacks while doing so.

Spellcasting. The [monster name] is a #-level spellcaster. Its spellcasting ability is [ability score] (spell save DC #, +# to hit with spell attacks). The [monster name] has following [class name] spells prepared:
Cantrips (at will): [spell name], [spell name]
1st level (# slots): [spell name], [spell name]

Multiattack. The Warden makes three attacks: two with Thorned Vines and one with Grasping Roots.

Thorned Vines. Melee Weapon Attack: +11 to hit, reach 10 ft., 1 target. Hit: 18 (2d10 + 6) piercing damage and 7 (2d6) poison damage. The target must succeed on a DC 17 Strength saving throw or be pushed 10 feet.

Grasping Root. (Recharge 5-6) The Warden summons thick roots from the ground in a 20-foot radius centered on itself. Each creature in the area must make a DC 17 Strength saving throw or be restrained for 1 minute. Restrained targets may repeat the save at the end of each of their turns.

Cradle the Rotten. (3/Day) The Warden causes a 10-foot radius patch of rot to bloom beneath a fallen ally. That ally regains 4d10 hit points and becomes resistant to all damage until the end of their next turn. 

Sporebrand. (1/Turn) When a creature hits the Warden with a melee attack, it may choose to brand them with a spore sigil. For 1 minute, the branded creature takes 5 psychic damage at the end of each turn it doesn’t target the Warden with an attack or spell.

The Warden can take 2 legendary actions, choosing from the options below.

Entangling Reach (Costs 1 Action). Make one Thorned Vines attack.

Rotshift (Costs 1 Action). Shift into the ground and emerge in an unoccupied space within 30 feet.

Bloom of Decay (Costs 2 Actions). Animate a rotting plant husk within 20 feet to explode. Each creature within 10 feet of it must make a DC 17 Constitution saving throw or take 21 (6d6) necrotic damage and be blinded until the end of their next turn.