Arborcyte

Shearing. Whenever the arborcyte suffers 10 or more damage from a single attack, a length of its vines breaks free. This animated tendril is under the arborcyte's control, moving and acting as an extension of the creature. Each tendril has AC 14, 10 hp, and a speed of 10 feet.

Multiattack. The arborcyte makes two thorn vine attacks plus one animated tendril attack for each tendril it can see that has been created through its Shearing trait.

Thorn Vine. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 18 (3d8 + 5) piercing damage, and the target is grappled (escape DC 16). Until this grapple ends, the target takes 7 (2d6) acid damage at the start of each of the arborcyte's turns, and tendril attacks against the target have advantage. The arborcyte can grapple up to two creatures at one time.

Animated Tendril. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 9 (1d8 + 5) piercing damage.