le medium amphibious dragon 

Perception +11; darkvision

Skills Acrobatics +8, Arcana +11, Athletics +12, Deception +9, Diplomacy +11, Intimidation +11, Nature +9, Occultism +12, Society +9, Stealth +10

Str +4 Dex +1 Con +3 Int +1 Wis +1 Cha +3

AC  22; Fort +11, Ref +11, Will +12

HP 60; Immunities sleep

Twisting Tail [R] When a creature within 10 feet uses a move action or leaves a square during a move action it's using, the dragon can use their reaction to make a tail Strike at the creature with a –2 penalty. If it hits, the creature stops moving in the square it was in when the dragon used this reaction.

Speed 30 feet, fly 80 feet, swim 20 feet

Melee [>] jaws +14 (poison), Damage 2d8 + 4 piercing plus 1d4 poison

Melee [>] claw +14 (agile), Damage 2d6 + 4 slashing

Melee [>] tail +12 (reach 10 feet), Damage 1d8 + 4 bludgeoning

Melee [>] horn +12, Damage 1d12 + 4 bludgeoning

Breath Weapon [>>] (arcane, evocation, poison) The dragon breathes a toxic cloud that deals 5d6 poison damage in a 30-foot cone. Each creature in the area must attempt a DC 24 basic Reflex save. The dragon can't use Breath Weapon again for 1d4 rounds.

Draconic Frenzy [>>] The dragon makes two claw Strikes and one tail Strike in any order.

Draconic Momentum When the dragon gets a critical success on a Strike, they recharge their Breath Weapon.

Beginner Box, page 60.