Atlach-Nacha, The Eldest Queen

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

Web Walker. The spider ignores movement restrictions caused by webbing.

Hatchlings. When encountered the Spider Queen of the Eldest will spawn 1d4+2Grue minions within 10ft of her. As a bonus action the Spider Queen of the Eldest can consume a Grue within 10ftto restore 2d10 hit points.

Multiattack. The Spider Queen of the Eldest makes two claw attacks and one sting attack.

Claw. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: (3d8 +2) piercing damage.

Sting. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: (3d8 +2) piercing damage, and the target must succeed on a DC 15 Constitution savingthrow or take 14 (4d6) poison damage. If poisoned, the part of the creature's body that was hitted get paralized for 1 hour.

Web. Ranged Weapon Attack: +8 to hit, ranged 20/60 ft., one Small, Medium, or Large creature. Hit: The target is restrained until it escapes the web. Any creaturecan use its action to make a DC 15 Strength check to free itself or another creaturein the web, ending the effect on a success. Dealing 15 slashing damage to the net (AC 12) destroys the net and frees the target.

The Spider Queen of the Eldest can take two legendary actions per round onlywhen bloodied.

Acid Spray (Costs 1 Actions). The Spider Queen of the Eldest spits acid in a linethat is 30 feet long and 5 feet wide. Each creature in that line must make a DC  14 Dexterity saving throw, taking 10 (3d6) acid damage on a failed save, or half asmuch damage on a successful one.

Maddening Fear (Costs 1 Action). The Spider Queen of the Eldest digs deep intothe psyche of it's target and summons its most primal fear. A creature within 30ftmust make a DC 14 Wisdom saving throw or become frightened.

Grue-nades (Costs 2 Actions). The Spider Queen of the Eldest causes her Gruehatchlings to explode forcing all players to make a DC 14 Dexterity saving throw, for every Grue within 10ft, or take 10 (3d6) acid damage, or half as much on a successful save.