Spider Climb. The Arachna Queen can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Sunlight Sensitivity. While in sunlight, the Arachna Queen has disadvantage on attack rolls, as well as on Wisdom Perception checks that rely on sight.

One with Shadow. The Arachna Queen can use a bonus action to hide if in dim light or darkness

Legendary Resistance (3/Day). If the Arachna Queen fails a saving throw, it can choose to succeed instead.

Web Walker. The Arachna Queen ignores movement restrictions caused by webbing.

*Weak Spot* Any attack aimed (disadvantage on attack) at the underbody of the Arachna Queen deals double damage.

Multiattack. The Arachna Queen makes 2 stab and one bite attacks

Stab. Melee Weapon Attack: +10 to hit, reach 15 ft., 1 target. Hit: 14 (2d8 + 5) piercing damage. 

Bite. Melee Weapon Attack: +10 to hit, reach 15 ft., 1 target. Hit: 14 (2d8 + 5) piercing damage and 18 (5d6) poison damage. 

Acid Spray. (Recharge 5-6) The Arachna Queen exhales acid in a 60-­foot line that is 5 feet wide. Each creature in that line must make a DC 17 Dexterity saving throw, taking 54 (12d8) acid damage on a failed save, or half as much damage on a successful one.

The Arachna Queen can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The Arachna Queen regains spent legendary actions at the start of its turn.

Leap (1 Action) The Arachna Queen leaps into the air and lands up to 20 feat away. This movement does not provoke attacks of opportunity.

Spawn Egg (1 action) The Arachna Queen spawns an egg that has 1 hp and an AC of 10. If the Egg is not destroyed, after 1 round, the egg will hatch into a giant spider.

Web Shot (2 Actions)  The Arachna Queen spits a strong webbing at one enemy within 20 feet. The target must succeed on a DC 17 Dexterity saving throw or be restrained. A creature that is restrained in this manner can make a DC 13 Strength Saving throw to break out of the web or can attack the webbing with a slashing attack to destroy the webbing. (10 AC and 10 HP)