Wailing Wightwillow

Shadowfallen. The Wightwillow can magically enter the Shadowfell from The Material Plane, or vice versa.

Innate Spellcasting. Spell Attack: +8, Save DC: 16
At will: Dancing Lights, Sapping Sting, Thorn Whip
3/Day: Fear, Grasping Vine
1/Day each: Blight, Spirit Shroud

Blight Breath (Recharge 5-6). The Wightwillow spews petrifying gas in a line 60 feet long and 5 feet wide. Each creature in that area hears an ear-piercing screech and must succeed on a DC 16 Constitution saving throw.
On a failed save, a target begins to turn into a Wightwillow tree and is Restrained.The Restrained target must repeat the saving throw at the end of its next turn. On a success, the Effect ends on the target. On a failure, the target is Petrified as a Wightwillow tree until freed by the Greater Restoration spell or other magic.
While in this form, an amount of materials sufficient to be made into a Wightwillow Wand will be shed by the tree every 7 days.

Spell. The Wightwillow casts a spell.

Whomp Attack. Melee Weapon Attack: +10 to hit, reach 10 ft., 1 target. Hit: 15 (3d8 + 6) bludgeoning damage. The target must make a DC 18 Strength saving throw or be either pushed back 10 feet or grappled.

Thorn Barrage. Ranged Weapon Attack: +10 to hit, range 20/80 ft., 1 target plus all within 5 feet of target. Hit: 11 (2d8 + 6) piercing damage.

Blink. The Wightwillow can activate its shadowy nature in a more rapid-fire way. At the end of each of the Willow's turns, the DM rolls a d20. On a roll of 11 or higher, the Willow vanishes to the Shadowfell, reappearing at the start of its next turn within 10 feet of its previous location. If it begins its turn in the Shadowfell, it instead vanishes to the Material Plane in a similar fashion. This effect can be ended as a bonus action.

Extra Attack. The Willow makes either a Whomp or Barrage attack.

Personal Space. When a creature comes within 10 feet, the Wightwillow can use its reaction to make a Whomp Attack against that creature.