large Dragon
Armor Class 18 (natural armor)
Hit Points 175
Speed fly +80, walk +40, burrow +20
Challenge 9
Saving Throws cha +7, con +8, dex +4, int +2, str +5, wis +5
Damage Immunities lightning
Senses darkvision 120 ft., keensense 30 ft.
Languages Common,Draconic
Charged Hide. When the blue dragon hasn't exhaled its Lightning Breath, the electric charge builds up across its body. While the dragon's Lightning Breath is available, it emits wild sparks of electricity, and each creature that starts its turn within 10 feet of the dragon must succeed on a DC 16 CON save or be incapacitated until the start of its next turn.
Multiattack. The dragon makes one Bite attack and two Claw attacks.
Bite. _Melee Weapon Attack:_ +9 to hit, reach 10 ft., one target. _Hit:_ 16 (2d10+5) piercing damage plus 5 (1d10) lightning damage.
Claw. _Melee Weapon Attack:_ +9 to hit, reach 5 ft., one target. _Hit:_ 12 (2d6+5) slashing damage.
Lightning Breath (Recharge 5-6). The dragon exhales lightning in a 60-foot line that is 5 feet wide. Each creature in that line must make a DC 16 DEX save, taking 55 (10d10) lightning damage on a failed save, or half as much damage on a successful one.
Source: Black Flag SRD · OGL/Open