Drider Spellcaster

Source: Monster Manual p. 120. Available in the SRD

"name": "Drider Spellcaster"
"size": "Large"
"type": "monstrosity"
"alignment": "Chaotic Evil"
"ac": !!int "19"
"ac_class": "natural armor"
"hp": !!int "123"
"hit_dice": "13d10 + 52"
"modifier": !!int "3"
"stats":
  - !!int "16"
  - !!int "16"
  - !!int "18"
  - !!int "13"
  - !!int "16"
  - !!int "12"
"speed": "30 ft., climb 30 ft."
"skillsaves":
  - "name": "Perception"
    "desc": "+5"
  - "name": "Stealth"
    "desc": "+9"
"gear":
  - "longbow"
  - "longsword"
"senses": "darkvision 120 ft., passive Perception 15"
"languages": "Elvish, Undercommon"
"cr": "6"
"traits":
  - "desc": "The drider is a 7th-level spellcaster. Its spellcasting ability is Wisdom\
      \ (spell save DC 14, +6 to hit with spell attacks). The drider has the following\
      \ spells prepared from the cleric spell list:\n\n**Cantrips (at will):** poison\
      \ spray, thaumaturgy\n\n**1st level (4 slots):** bane, detect magic, sanctuary\n\
      \n**2nd level (3 slots):** hold person, silence\n\n**3rd level (3 slots):**\
      \ clairvoyance, dispel magic\n\n**4th level (2 slots):** divination, freedom\
      \ of movement"
    "name": "Spellcasting"
  - "desc": "The drider has advantage on saving throws against being charmed, and\
      \ magic can't put the drider to sleep."
    "name": "Fey Ancestry"
  - "desc": "The drider can climb difficult surfaces, including upside down on ceilings,\
      \ without needing to make an ability check."
    "name": "Spider Climb"
  - "desc": "While in sunlight, the drider has disadvantage on attack rolls, as well\
      \ as on Wisdom (Perception) checks that rely on sight."
    "name": "Sunlight Sensitivity"
  - "desc": "The drider ignores movement restrictions caused by webbing."
    "name": "Web Walker"
"actions":
  - "desc": "The drider makes three attacks, either with its longsword or its longbow.\
      \ It can replace one of those attacks with a bite attack."
    "name": "Multiattack"
  - "desc": "*Melee Weapon Attack:* +6 to hit, reach 5 ft., one creature. *Hit:* 2\
      \ (1d4) piercing damage plus 9 (2d8) poison damage."
    "name": "Bite"
  - "desc": "*Melee Weapon Attack:* +6 to hit, reach 5 ft., one target. *Hit:* 7 (1d8\
      \ + 3) slashing damage, or 8 (1d10 + 3) slashing damage if used with two hands."
    "name": "Longsword"
  - "desc": "*Ranged Weapon Attack:* +6 to hit, range 150/600 ft., one target. *Hit:*\
      \ 7 (1d8 + 3) piercing damage plus 4 (1d8) poison damage."
    "name": "Longbow"
"source":
  - "MM"

Environment

underdark