Avassh, The Twister of Roots (Eberron)

Alien Mind. If a creature deals psychic damage to Avassh or tries to read it's thoughts, that creature must succeed on a DC 22 intelligence saving throw or be stunned for 1 minute.  The stunned creature can repeat the saving throw at the end of its turns, ending the effect on a success.

Blight Spores. When Avassh uses its Ligneous Claw or Infectious Growth, it has a chance of infecting creatures with a blight disease carried by its corrupted spores.  A diseased creature suffers the following cumulative effects for each blight spore infecting it:

• Its hit point maximum is reduced by 10.
• When it makes a saving throw against any of Avassh's effects, it must roll a d4 and subtract the number rolled from the saving throw.

Legendary Resistance (3/day).  If Avassh fails a saving throw, it can choose to succeed instead.

Magic Resistance.  Avassh has advantage on saving throws against spells and other magical effects.

Regeneration.  Avassh regains 20 hit points at the start of its turn.  If Avassh takes radiant damage, this trait doesn't function at the start of Avassh's next turn.  Avassh dies only if it starts its turn with 0 hit points and doesn't regenerate.

Ruinous Seed.  At the start of its turn, Avassh grows a Medium seed pod in an unoccupied space it can see within 30 feet of it.  A seed pod has AC 12 and 50 hp.  Creatures within 5 feed of the seed pod when it grows take 7 (2d6) necrotic damage.

Multiattack. Avassh makes two Ligneous Claw attacks and two Thrashing Vines attacks.

Ligneous Claw. Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 17 (3d6 + 7) [slashing] damage, and the target is infected with a blight spore.

Thrashing Vines. Melee Weapon Attack: +14 to hit, reach 30 ft., one target. Hit: 18 (2d10 + 7) [slashing] damage, and the target is restrained until the end of its next turn.

Mourning Bloom. Avassh grows a bloom of haunting roses from a point it can see within 120 feet of it, and the roses cry out with the voices of the blood that fertilizes their soil.  Each creature in a 30-foot-radius sphere centered on that point must make a DC 22 Wisdom saving throw.  On a failed save, a creature takes 22 (4d10) psychic damage and becomes frightened of Avassh.  On a successful save, a creature takes half as much damage and is not frightened.  A frightened creature must repeat the saving throw at the end of each of its turns, taking 22 (4d10) psychic damage on a failed save, and ending the effect on itself on a successful one.

Rootbinding.  Avassh attempts to remake one creature it can see within 30 feet of it into a twisted tree.  The target must make a DC 22 Constitution saving throw.  On a successful save, the target narrowly escapes being remade, and instead takes 55 (10d10) necrotic damage.  On a failed save, the target's body is twisted into the form of a Large Tree, becoming paralyzed and rootbound.
     A rootbound creature must make a DC 22 Constitution saving throw at the start of each of its turns.  On a failed save, it is paralyzed until the start of its next turn.  On a successful save, it is no longer paralyzed, but has disadvantage on attack rolls and ability checks, and its speed is reduced to 10 feet.  The creature continues making this saving throw at the start of each of its turns until it either succeeds twice or fails twice (not including the initial failure that made the creature rootbound).  If the creature succeeds twice, the effect ends and the creature takes 55 (10d10) necrotic damage.  If the creature fails twice, the effect ends, the creature dies, and it is turned into an inanimate tree; this transformation can be undone only by a wish spell.

Teleport. Avassh teleports up to 30 feet to an unoccupied space it can see.

Avassh can take 3 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.  Avassh regains spent legendary actions at the start of its turn.

Vine Whip. Avassh makes a Thrashing Vine attack.
Burst Seed Pod.  Avassh chooses one seed pod it can see that was created by its Ruinous Seed.  That seed pod is destroyed and explodes in a 20-foot radius cloud of noxious fumes.  Creatures within the fumes must make a DC22 Constitution saving throw, taking 22 (5d8) poison damage on a failed save, affected even if they hold their breath or don't need to breathe.
Rebirth (Costs 3 Actions).  Avassh discards its current body and reemerges from one of its seed pods, destroying the seed pod in the process.  Avassh ends all diseases and conditions afflicting it, and if it has fewer than half its maximum hit points, it reemerges with half its maximum hp (143).  Avassh can use this legendary action while incapacitated.

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