Armor Class 16 (natural armor)
Hit Points 370 (20d20 + 160)
Speed 50 ft., burrow 30 ft.
Saving Throws STR +15, CON +15
Damage Resistances cold, lightning
Damage Immunities acid, fire, poison, [object Object]
Condition Immunities charmed, exhaustion, frightened, poisoned
Senses truesight 120 ft., passive Perception 15
Languages Abyssal, telepathy 120 ft.
Challenge 22
Heat Regeneration. If the temperature around it is 100 degrees Fahrenheit or higher, Aurnozci regains 15 hit points at the start of its turn. If it takes cold or radiant damage, this trait doesn't function at the start of its next turn. Aurnozci dies only if it starts its turn with 0 hit points and doesn't regenerate.
Legendary Resistance (3/Day). If Aurnozci fails a saving throw, it can choose to succeed instead.
Magic Resistance. Aurnozci has advantage on saving throws against spells and other magical effects.
Multiattack. Aurnozci makes one Bite attack and two Tail attacks.
Bite. Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 21 (2d12 + 8) slashing damage plus 9 (2d8) fire damage.
Tail. Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 17 (2d8 + 8) bludgeoning damage.
Mucus Spray (Recharge 5–6). Aurnozci sprays mucus in a 60-foot cone. Each creature in that cone must make a DC 20 Dexterity saving throw, taking 42 (12d6) acid damage on a failed save, or half as much damage on a successful one.
Move. Aurnozci moves up to its speed.
Tail. Aurnozci makes one Tail attack.
Cast a Spell (Costs 2 Actions). Aurnozci uses Spellcasting.
Conflagration (Costs 2 Actions). Flames momentarily surround Aurnozci. Each creature within 15 feet of Aurnozci must make a DC 20 Dexterity saving throw, taking 18 (4d8) fire damage on a failed save, or half as much damage on a successful one.
BMT, p. 167