Multiattack

The vine drake can make three attacks: one with its bite, one with its claw, and one with its vine lash.

Bite

Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 8 (1d8 + 4) piercing damage plus 4 (1d8) poison damage. The target must succeed on a DC 14 Constitution saving throw or be poisoned for 1 minute. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Claw

Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 7 (1d6 + 4) slashing damage.

Vine Lash

Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 8 (1d8 + 4) bludgeoning damage. The target is grappled (escape DC 15) if it is a Medium or smaller creature. Until this grapple ends, the target is restrained, and the vine drake can't vine lash another target.

Acid Breath (Recharge 5-6)

The vine drake exhales acid in a 30-foot line that is 5 feet wide. Each creature in that line must make a DC 14 Dexterity saving throw, taking 22 (5d8) acid damage on a failed save, or half as much damage on a successful one.