b'Ancient Nightmare Dragon \n'b'  Family:   Dragons  \n'b'  Gargantuan   dragon ,  neutral evil  \n'b'  Armor Class  20 (natural armor)  Hit Points  351 (18d20 + 162)  Speed  40 ft., fly 80 ft.\n'b' STATS STR: 30 (+10) DEX:  15 (+2)  CON:  29 (+9)  INT:  18 (+4)  WIS:  17 (+3)  CHA:  28 (+9)  \n'b'\n'b'\n'b'\n'b'\n'b'\n'b'\n'b'  Saves   Dex  +8,  Con  +15,  Wis  +10,  Cha  +15  Skills   Perception  +16,  Stealth  +8  Senses  blindsight 60 ft.,  darkvision  120 ft., passive  Perception   Languages  Common, Draconic  Challenge  20 (25,000 XP) \n'b' SPECIAL TRAITS \n'b'\n'b'  Dreamsight . With a brief glance, a nightmare dragon can see a hazy image of the current dreams of sleeping creatures. \n'b'  Legendary Resistance (3/Day) . If the dragon fails a saving throw, it can choose to succeed instead. \n'b'  Master of Dreams . A nightmare dragon cannot be magically put to sleep. \n'b'  Rising Nightmares . When a nightmare dragon kills a nonconstruct, non-undead, it may cast  phantasmal killer  using a bonus action. The spell requires no spell slot or components, and has a Cha-based spellcasting DC of 23. \n'b'  See in Darkness . A nightmare dragon can see in magical  darkness . \n'b'\n'b' ACTIONS \n'b'\n'b'  Multiattack . The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws. \n'b'  Bite .  Melee Weapon Attack : +16 to hit, reach 15 ft., one target.  Hit : 21 (2d10 + 10) piercing damage. \n'b'  Claw .  Melee Weapon Attack : +16 to hit, reach 10 ft., one target.  Hit : 17 (2d6 + 10) slashing damage. \n'b'  Tail .  Melee Weapon Attack : +16 to hit, reach 20 ft., one target.  Hit : 19 (2d8 + 10) bludgeoning damage. \n'b'  Frightful Presence . Each creature of the dragon\xe2\x80\x99s choice that is within 120 feet of the dragon and aware of it must succeed on a DC 23  Wisdom  saving throw or become  frightened  for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature\xe2\x80\x99s saving throw is successful or the effect ends for it, the creature is immune to the dragon\xe2\x80\x99s Frightful Presence for the next 24 hours. \n'b'  Acid Breath (Recharge 5-6) . The dragon exhales acid in a 90-foot cone. Each creature in that area must make a DC 23  Dexterity  saving throw, taking 72 (16d8) acid damage on a failed save, or half as much damage on a successful one. \n'b'  Change Shape . The dragon magically polymorphs into a humanoid that has a challenge rating no higher than its own, or back into its true form. It reverts to its true form if it dies. Any equipment it is wearing or carrying is absorbed or borne by the new form (the dragon\xe2\x80\x99s choice). In a new form, the dragon retains its alignment,  Hit Points , Hit Dice, ability to speak, proficiencies, Legendary Resistance, lair  actions , and  Intelligence ,  Wisdom , and  Charisma  scores, as well as this action. Its statistics and capabilities are otherwise replaced by those of the new form, except any class features or Legendary Actions of that form. \n'b'\n'b' LEGENDARY ACTIONS \n'b' 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\xe2\x80\x99s turn. The dragon regains spent Legendary Actions at the start of its turn. \n'b'\n'b'  Detect . The dragon makes a  Wisdom  ( Perception ) check. \n'b'  Tail Attack . The dragon makes a tail  attack .'