Amberweaver

Multiattack. The Amberweaver makes two attacks with its claws.

Crazed Strength. When the Amberweaver has fewer than 30 hit points, it gains a +2 bonus to attack and damage rolls.

Insanity. The Amberweaver cannot be charmed or frightened.

Dexterous Movement. Opportunity attacks against the Amberweaver have disadvantage.

Vicious Claw. Melee Weapon Attack: +4 to hit, reach 5 ft., 1 target. Hit: 8 (2d6 + 2) Slashing damage.

Preserving Grasp. The Amberweaver attempts to grapple a creature or object. If it succeeds, the creature's lower body becomes covered in solid magical amber, reducing its speed to 0. On its turn, if it is not still being grappled, the creature can make a DC 14 Strength check to break free from the amber. If it is still being grappled, if it fails to escape again, it becomes completely encased in amber. On its next turn, it may make a DC 18 Strength check to break free, but if it fails, it becomes Petrified and Unconscious until the amber is destroyed. A creature encased in the magical amber regains 1d12 hit points every hour but never becomes conscious unless it is freed.

Preserving Touch. The Amberweaver attempts to hold a Medium or smaller object within 5 feet of it. If it maintains contact with the object until the start of its next turn, if the object is nonmagical, it becomes encased in amber. If the object was a melee weapon, it may be used as an improvised weapon which deals 1d4 Bludgeoning damage. If it was a ranged weapon, it becomes unusable.

Amber that is holding a creature has 40 hit points and an armor class of 16. Amber that is holding an object has 10 hit points and an armor class of 12.