Flexing coil. Creatures that see the emerald dragon for the first time within 24 hours must make a DC 14 perception check or the dragon has advantage on attacking that creature for the first round of combat. 

Innate Spellcasting (Psionics). The young emerald dragon's innate spellcasting ability is Intelligence (DC 12). The young emerald dragon can innately cast the following spells, requiring no material components:

At will: fog cloud, greater invisibility, identify, plane shift, suggestion (verbal only required)

Multi attack. The emerald dragon makes a bite attack and two claw attacks. 

Bite. Melee Weapon Attack: +1 to hit, reach 5 ft., 1 target. Hit: 3 (1d8 - 1) piercing damage. 

Claw. Melee Weapon Attack: +1 to hit, reach 5 ft., 1 target. Hit: 1 (1d4  - 1) slashing damage. 

Sonic vibration breath. The dragon exhales a wave of sonic vibrations. Each creature within a 30ft cone must make a DC 11 Constitution saving Throw or be knocked unconscious for 1d4 minutes. On a successful save the target is deafened for 1d4 minutes. To wake a sleeping creature a character can use their bonus action to wake them allowing the creature to make the save again, other gem dragons are immune to this breath weapon.