b'Undead Dragon \n'b'  Gargantuan   undead  (dragon),  chaotic evil  \n'b'  Armor Class  22 (natural armor)  Hit Points  546 (28d20 + 252)  Speed  40 ft., fly 80 ft., swim 40 ft.\n'b' STATS STR: 30 (+10) DEX:  14 (+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'     Saving Throws   Dexterity  +10,  Constitution  +17,  Wisdom  +11,  Charisma  +17  Skills   Insight  +11,  Perception  +19  Senses   darkvision  60 ft., passive  Perception  29  Languages  \xe2\x80\x93  Challenge  26 (90,000 XP) \n'b' Special Traits \n'b'\n'b'   Legendary Resistance (3/day) . If the undead dragon fails a saving throw, it can choose to succeed instead. \n'b'  Regeneration . The undead dragon regains 30  hit points  at the start of its turn if it has at least 1 hit point and isn\xe2\x80\x99t in sunlight. If the undead dragon takes radiant damage or damage from holy water, this trait doesn\xe2\x80\x99t function at the start of the undead dragon\xe2\x80\x99s next turn. \n'b'  Soul Consumption . When a creature dies within 30 feet of the undead dragon, that creature must succeed on a DC 18  Wisdom  saving throw or that creature\xe2\x80\x99s soul is torn from its body and pulled into the undead dragon\xe2\x80\x99s gaping maw. The undead dragon gains a number of  temporary hit points  equal to the dead creature\xe2\x80\x99s Hit Dice. Creatures that die in this manner can only be restored to life by a  true resurrection  or  wish  spell. \n'b'  Spellcasting . The undead dragon is an 18th-level spellcaster. Its spellcasting ability is  Charisma  (spell save DC 25, +17 to hit with spell attacks). It can cast the following spells:\n'b'\n'b'   Cantrips (at will) :  chill touch , fire bolt,  mage hand ,  mending ,  prestidigitation ,  ray of frost  \n'b'  1st level (4 slots) :  burning hands ,  magic missile ,  protection from evil and good ,  thunderwave  \n'b'  2nd level (3 slots) :  blindness/deafness ,  flaming sphere ,  ray of enfeeblement ,  scorching ray  \n'b'  3rd level (3 slots) :  blink ,  dispel magic ,  fireball ,  gaseous form ,  gust of wind ,  haste  \n'b'  4th level (3 slots) :  confusion ,  fire shield ,  greater invisibility ,  wall of fire  \n'b'  5th level (3 slots) :  arcane hand ,  cone of cold ,  mislead ,  wall of stone  \n'b'  6th level (1 slot) :  chain lightning ,  circle of death ,  irresistible dance  \n'b'  7th level (1 slot) :  forcecage ,  prismatic spray  \n'b'  8th level (1 slot) :  control weather ,  maze  \n'b'  9th level (1 slot) :  foresight ,  time stop  \n'b'\n'b'  Actions \n'b'\n'b'   Multiattack . The undead dragon can use its Frightful Presence and make three attacks: one with its bite and two with its claws. \n'b'  Bite .  Melee Weapon Attack : +18 to hit, reach 15 ft., one target.  Hit : 26 (3d10 + 10) piercing damage plus 21 (6d6) necrotic damage. The target\xe2\x80\x99s hit point maximum is reduced by an amount equal to the necrotic damage taken, and the undead dragon regains  hit points  equal to that amount. The reduction lasts until the target finishes a  long rest . The target dies if this effect reduces its hit point maximum to 0. \n'b'  Claws .  Melee Weapon Attack : +18 to hit, reach 10 ft., one target.  Hit : 23 (3d8 + 10) slashing damage. The target is  grappled  (escape DC 24) if the undead dragon isn\xe2\x80\x99t already grappling a creature, and the target is  restrained  until this grapple ends. \n'b'  Tail .  Melee Weapon Attack : +18 to hit, reach 20 ft., one target.  Hit : 19 (2d8 + 10) bludgeoning damage. \n'b'  Frightful Presence . Each creature of the undead dragon\xe2\x80\x99s choice that is within 120 feet of the dragon and aware of it must succeed on a DC 24  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 undead dragon\xe2\x80\x99s Frightful Presence for the next 24 hours. \n'b'  Change Shape . The undead dragon magically polymorphs into a humanoid or beast 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'  Breath Weapons (Recharge 5-6) . The undead dragon uses one of the following breath weapons. \n'b'  Fire Breath . The undead dragon exhales fire in a 90-foot cone. Each creature in that area must make a DC 24  Dexterity  saving throw, taking 82 (15d10) fire damage on a failed save, or half as much damage on a successful one. \n'b'  Weakening Breath . The undead dragon exhales gas in a 90-foot cone. Each creature in that area must succeed on a DC 24  Strength  saving throw or have disadvantage on  Strength -based  attack  rolls,  Strength  checks, and  Strength  saving throws 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. \n'b'\n'b'  Legendary Actions \n'b' the undead dragon can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature\xe2\x80\x99s turn. The undead dragon regains spent legendary actions at the start of its turn. \n'b'\n'b'   Detect . The undead dragon makes a  Wisdom  ( Perception ) check. \n'b'  Tail Attack . The undead dragon makes a tail  attack . \n'b'  Wing Attack (Costs 2 Actions) . The undead dragon beats its wings. Each creature within 15 ft. of the undead dragon must succeed on a DC 25  Dexterity  saving throw or take 20 (3d6 + 10) bludgeoning damage and be knocked  prone . The undead dragon can then fly up to half its flying speed.'