Colossal Ice Spider

Saving Throws: DEX +6, CON +8, INT +1
Skills: Perception +5
Damage Immunities: Cold, Poison
Condition Immunities: Poisoned
Senses: Blindsight 15 ft. (Blinded by harsh light), Darkvision 60 ft., Passive Perception 15
Languages: --
Challenge: 12 (8,400 XP)
Proficiency Bonus: +4

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

Web Sense. While in contact with a web, the colossal ice spider knows the exact location of any other creature in contact with the same web.

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

Frost Aura. Any creature that starts its turn within 10 feet of the colossal ice spider takes 2d6 cold damage.

Multiattack. The colossal ice spider makes three attacks: one with its Bite and two with its Claws. It may swap out its Bite attack with either an Icy Sting, Web, or Pounce attack. It may replace all these attacks with an Entangle in Webs attack.

Bite. Melee Weapon Attack: +8 to hit, reach 5 ft., one creature. Hit: 11 (2d6 + 4) piercing damage, and the target must make a DC 16 Constitution saving throw, taking 18 (4d8) cold damage on a failed save, or half as much damage on a successful one. If the cold damage reduces the target to 0 hit points, the target is stable but frozen, taking 5 (1d10) cold damage at the start of each of its turns until it is healed.

Claw. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 2d6 + 4 slashing damage.

Pounce. Ranged weapon attack: range 30 ft., one target. Place the colossal ice spider in base contact with the target (closest available point from the initial attack location). The target must pass a DC 12 Acrobatics check or be knocked prone, taking 1d12 cold damage.

Icy Sting (Recharge 5–6). The colossal ice spider may attack one prone form in melee. Each creature in that area must make a DC 15 Dexterity saving throw or roll a DC 15 Constitution saving throw, taking 5d6 cold damage on a failed save, or half as much damage on a successful one.

Freezing Web (Recharge 5–6). The spider launches a 10 ft sphere web imbued with icy energy within 30 feet of it. The target must succeed on a DC 15 DEX save or be restrained and take 1d10 cold damage at the start of each of its turns. A creature, including the restrained target, can take its action to free the target from the webbing by succeeding on a DC 15 STR check. The webbing can also be attacked and destroyed (AC 10; HP 10; vulnerability to fire damage; immunity to cold, bludgeoning, poison, and psychic damage).

Icy Leap. The spider can make a high, icy leap up to 20 feet in any direction, landing in a burst of frost. Each creature within 5 feet of where the spider lands must make a DC 14 DEX save, taking 2d6 cold damage on a failed save, or half as much damage on a successful one.

Frozen Bite. As a bonus action, the spider can cause its next bite attack to deal an additional 1d6 cold damage. This effect lasts until the end of its next turn.

Icy Retaliation. When the colossal ice spider takes damage from a melee attack, it can use its reaction to deal 2d6 cold damage to the attacker.

Web Shield. When the colossal ice spider is hit by an attack, it can use its reaction to shoot a web at the attacker, imposing disadvantage on the attack roll. The webbing can be attacked and destroyed (AC 10; hp 5; vulnerability to fire damage; immunity to cold, bludgeoning, poison, and psychic damage).

Frost Leap. When an enemy ends its turn within 10 feet of the colossal ice spider, it can use its reaction to leap up to 20 feet to an unoccupied space it can see, avoiding any opportunity attacks. Any creature within 5 feet of its landing spot must make a DC 16 Dexterity saving throw or take 3d6 cold damage.

Ice Burst. When the colossal ice spider is reduced to 50 hit points or fewer, it can use its reaction to emit a burst of frost. All creatures within 10 feet of the spider must make a DC 16 Dexterity saving throw, taking 4d6 cold damage on a failed save, or half as much damage on a successful one.

Legendary Actions for the Ice Spider (3 per round)

• Icy Bite: The Ice Spider makes a bite attack.
• Frost Burst (2 actions): The Ice Spider emits a burst of frost. Each creature within 5 feet of the spider must succeed on a DC 13 Dexterity saving throw or take 3d10 cold damage.
• Ignite Web: The Ice Spider freezes any webbing it has created within 60 feet. Creatures in contact with the webbing must succeed on a DC 13 Dexterity saving throw or take 2d6 cold damage.