Ancient Emerald Dragon

Gargantuan dragon (gem), Typically Lawful Neutral
Armor Class 20 (natural armor)
Hit Points 332 (19d20 + 133)
Speed 40 ft., burrow 30 ft., fly 80 ft.
STR
25 (+7)
DEX
12 (+1)
CON
25 (+7)
INT
20 (+5)
WIS
18 (+4)
CHA
20 (+5)
Saving Throws Dex +8, Con +14, Wis +11, Cha +12
Skills Arcana +12, Deception +12, Perception +18, Stealth +8
Damage Resistances fire, psychic
Senses blindsight 60 ft., darkvision 120 ft., passive Perception 28
Languages Common, Draconic, telepathy 120 ft.
Challenge 21 (33000 XP)     Proficiency Bonus +7
Legendary Resistance (3/Day).
Tunneler.
Warp Perception (1/Day).
ACTIONS
Multiattack.
Bite.
Claw.
Disorienting Breath (Recharge 5–6).
Spellcasting (Psionics).
BONUS ACTIONS
Change Shape.
Psychic Step.
LEGENDARY ACTIONS
Claw.
Psionics (Costs 2 Actions).
Emerald Embers (Costs 3 Actions).

This full creature's stat block is not available (not OGL).

Fizban´s Treasury of Dragons
Ancient Emerald Dragon