Amaranth

One with Nature. Amaranth has advantage on all saving throws and attack rolls whilst in contact with plantlife

Natural Camo. Amaranth is indistinguishable from plantlife when stationary

Spellcasting. The Amaranth is a 20th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 15, +7 to hit with spell attacks). The Amaranth has following Conjuration spells prepared:
Cantrips (at will): Gust, Mold Earth, Poison Spray, Shape Water, Thorn Whip, Animal Friendship, Beast Bond, Speak with Animals, Spike Growth

Whipping Vines Melee Weapon Attack: +6 to hit, reach 10 ft., 1 target. Hit: 15 (2d6 + 3) Slashing damage. 

Swarm of Insects RangedWeapon Attack range 20/60ft., 1 target. Hit: 15 (2d6 + 3) Piercing damage.

Creeping Tendrils. If a creature gets within 5ft of the Amaranth and attempts to move away it must succeed on a DC15 Strength check or be held close by creeping tendrils

Amaranth can cause plantlife to grow around it (so long as it is standing on natural ground and not Rock or Stone or Water)

Grow Plants (Costs 1 Actions, Amaranth gets 3 legendary actions until it's next turn). Plant life grows at a rate of 5ft per action. If Amaranth uses 2 charges in the same area it can act as half cover or difficult terrain.