Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.

Rock Camouflage. While the dragon remains motionless with it’s eyes shielded, it resembles a natural  rock formation or a pile of fallen boulders . A creature within 30 feet of it can discern its true nature with a successful DC 19 intelligence (Nature) check.

Earth Mastery. The dragon has an incredible affinity with earth magic and can innately control many effects normally considered magical in nature.

-The dragon can cast an innate spell as a bonus action even if normally that spell effect would require an action .Additionally difficult terrain comprised of earth and stone does not impose a movement penalty.

 Subterranean Ambusher. The dragon needs to burrow atleast 25 feet to be completely submerged or it risks being attacked with part of its body exposed.

-Attacks of opportunity have disadvantage when this dragon submerges into the ground due rocks and soil being explosively displaced.

Multiattack. The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 25(3d10 + 9) piercing damage.

Claw. Melee Weapon Attack: +15 to hit, reach 5 ft., one target. Hit: 19 (3d6 + 9) slashing damage.

Tail. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 22 (3d8 + 9) bludgeoning damage.

Frightful Presence. Each creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 19 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's saving throw is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next 24 hours.

Innate Spell Casting Spell DC 19:   At Will: Move Earth,  Mold Earth, Meld Into Stone ,Maximilian's Earthen Grasp, Stone shape.

3/day: Earth Tremor(8), 

1/day: Wall of Stone,   Earthquake

 Petrification Breath (Recharge 5-6). The dragon exhales an eerie blast in a 60-foot cone. Each creature in that area must make a DC 22 Constitution saving throw,  turning to stone(petrified) on failure by 5 or more. creatures otherwise start to turn into stone and are restrained. At end of a creature's next turn repeat the saving throw and if fail again is petrified and ending the effect on success. The petrification lasts until the creature is freed by the greater restoration spell or other magic.

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.

Detect. The dragon makes a Wisdom (Perception) check.

Envious Gaze. The dragon innately casts Earthbind at a flying creature within range.

Tail Attack. The dragon makes a tail attack.

Delve Attack (Costs 2 Actions). The dragon rears back and dives into the ground. A creature on the ground within 40 feet of the dragon must succeed on a DC 23 Dexterity saving throw or take 21 (4d6 + 9) bludgeoning damage and be knocked prone as the dragon bursts through the ground under it's feet.