Young Brass Dragon

Large dragon, chaotic good

Armor Class 17 (natural armor)
Hit Points 110 (13d10 + 39)
Speed 40 ft., burrow 20 ft., fly 80 ft.

Saving Throws Dex +3, Con +6, Wis +3, Cha +5
Skills Perception +6, Persuasion +5, Stealth +3
Damage Immunities fire
Senses blindsight 30 ft., darkvision 120 ft., passive Perception 16
Languages Common, Draconic
Challenge 6 (2,300 XP)

Actions

Multiattack. The dragon makes three attacks: one with its bite and two with its claws.
Bite. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 15 (2d10 + 4) piercing damage.
Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) slashing damage.
Breath Weapons (Recharge 5–6). The dragon uses one of the following breath weapons.
Fire Breath. The dragon exhales fire in a 40-foot line that is 5 feet wide. Each creature in that line must make a DC 14 Dexterity saving throw, taking 42 (12d6) fire damage on a failed save, or half as much damage on a successful one.
Sleep Breath. The dragon exhales sleep gas in a 30-foot cone. Each creature in that area must succeed on a DC 14 Constitution saving throw or fall unconscious for 5 minutes. This effect ends for a creature if the creature takes damage or someone uses an action to wake it.