Multiattack

The vines of Nemthyr makes three attacks: two with its slam and one with its thorny lash.

Slam

Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) bludgeoning damage.

Thorny Lash

Melee Weapon Attack: +7 to hit, reach 15 ft., one target. Hit: 15 (2d10 + 4) slashing damage, and the target is grappled (escape DC 15). Until this grapple ends, the target is restrained. The vines of Nemthyr has two thorny lashes, each of which can grapple only one target.

Thorn Spray (Recharge 6)

The vines of Nemthyr shoots poisonous thorns in a 30-foot cone. Each creature in that area must make a DC 15 Constitution saving throw, taking 35 (10d6) poison damage on a failed save, or half as much damage on a successful one.