Young Bronze Dragon

Large dragon, lawful good

Armor Class 18 (natural armor)
Hit Points 142 (15d10 + 60)
Speed 40 ft., fly 80 ft., swim 40 ft.

Saving Throws Dex +3, Con +7, Wis +4, Cha +6
Skills Insight +4, Perception +7, Stealth +3
Damage Immunities lightning
Senses blindsight 30 ft., darkvision 120 ft., passive Perception 17
Languages Common, Draconic
Challenge 8 (3,900 XP)

Amphibious. The dragon can breathe air and water.

Actions

Multiattack. The dragon makes three attacks: one with its bite and two with its claws.
Bite. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 16 (2d10 + 5) piercing damage.
Claw. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 12 (2d6 + 5) slashing damage.
Breath Weapons (Recharge 5–6). The dragon uses one of the following breath weapons.
Lightning Breath. The dragon exhales lightning in a 60- foot line that is 5 feet wide. Each creature in that line must make a DC 15 Dexterity saving throw, taking 55 (10d10) lightning damage on a failed save, or half as much damage on a successful one.
Repulsion Breath. The dragon exhales repulsion energy in a 30-foot cone. Each creature in that area must succeed on a DC 15 Strength saving throw. On a failed save, the creature is pushed 40 feet away from the dragon.