Armor Class 15 (natural armor)
Hit Points 144 (17d10 + 51)
Speed 20 ft.
Saving Throws Dex +6, Con +6, Int +7
Skills Athletics +5, Perception +3, Stealth +6
Damage Immunities poison
Condition Immunities charmed, poisoned, unconscious
Senses darkvision 240 ft., passive Perception 13
Languages Common, Void Speech
Challenge 7 (2,900 XP)
Eldritch Understanding. The spider of Leng can read and use any spell scroll or magic item, ignoring all class, race, and level requirements.
Poisonous Blood. A creature that hits the spider of Leng with a melee attack while within 5 feet of it takes 4 (1d8) poison damage.
Poisonous Death. When the spider of Leng dies, the poisonous blood in its body vaporizes, forming a cloud in the spider's space until initiative count 20 on the next round. Each creature within 5 feet of the spider and each creature that enters the cloud for the first time on a turn must make a DC 15 Constitution saving throw, taking 9 (2d8) poison damage on a failed save, or half as much damage on a successful one.
Multiattack. The spider of Leng makes two Claw attacks and one Staff of Leng attack, or it makes three Spit Venom attacks.
Claw. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) slashing damage plus 4 (1d8) poison damage.
Staff of Leng. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 7 (1d6 + 3) bludgeoning damage plus 7 (2d6) psychic damage, and the target must succeed on a DC 15 Wisdom saving throw or be stunned until the end of is next turn.
Spit Venom. Ranged Weapon Attack: +6 to hit, range 20/60 ft., one target. Hit: 16 (3d8 + 3) poison damage, and the target must succeed on a DC 15 Constitution saving throw or be poisoned and blinded until the end of its next turn.
Spellcasting. The spider of Leng casts one of the following spells, requiring no material components and using Intelligence as the spellcasting ability (spell save DC 15):
At will: comprehend languages, detect magic
3/day each: confusion, silence
1/day each: arcane eye, hypnotic pattern
Poisonous Riposte. The spider of Leng adds 3 to its AC against one melee attack that would hit it. To do so, the spider must see the attacker. If this effect causes the attack to miss, the attacker takes 4 (1d8) poison damage.