Ancient Deep Dragon

Gargantuan dragon, typically neutral evil

Armor Class

20 (natural armor)

Hit Points

201 (13d20 + 65)

Speed

walk 40 ft., burrow 40 ft., fly 80 ft., swim 40 ft.

Saves

Dex +9, Con +11, Wis +10, Cha +11

Skills

Perception +10, Persuasion +17, Stealth +15

Damage Resistances

poison, psychic

Condition Immunities

charmed, frightened, poisoned

Senses

blindsight 60 ft., darkvision 300 ft.

Languages

Common, Draconic, Undercommon

Challenge

18

Proficiency Bonus

+6

Legendary Resistance (3/Day)

If the dragon fails a saving throw, it can choose to succeed instead.

Actions

Multiattack

The dragon makes one Bite attack and two Claw attacks.

Bite

Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 17 (2d10 + 6) piercing damage plus 11 (2d10) poison damage.

Claw

Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 13 (2d6 + 6) slashing damage.

Tail

Melee Weapon Attack: +12 to hit, reach 15 ft., one target. Hit: 10 (1d8 + 6) bludgeoning damage. If the target is a creature, it must succeed on a DC 20 Strength saving throw or be knocked prone.

Change Shape

The dragon magically transforms into any creature that is Medium or Small, while retaining its game statistics (other than its size). This transformation ends if the dragon is reduced to 0 hit points or uses an action to end it.

Nightmare Breath (Recharge 5-6)

The dragon exhales a cloud of spores in a 90-foot cone. Each creature in that area must make a DC 19 Wisdom saving throw. On a failed save, the creature takes 49 (9d10) psychic damage, and it is frightened of the dragon for 1 minute. On a successful save, the creature takes half as much damage with no additional effects. A frightened creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Legendary actions

Legendary Actions (3/Turn)

The dragon 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 dragon regains spent legendary actions at the start of its turn.

Commanding Spores

The dragon exhales a cloud of spores in a 90-foot cone. Each creature in that area must make a DC 19 Wisdom saving throw. On a failed save, the creature takes 49 (9d10) psychic damage, and it is frightened of the dragon for 1 minute. On a successful save, the creature takes half as much damage with no additional effects. A frightened creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Tail

The dragon makes one Tail attack.

Spore Salvo (Costs 2 Actions)

The dragon releases poisonous spores around a creature within 30 feet of it that it can see. The target must succeed on a DC 19 Constitution saving throw or take 28 (8d6) poison damage and become poisoned for 1 minute. The poisoned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.