Amphibious. Yorb can breathe air and water.
Poisonous Skin. Any creature that grapples Yorb or otherwise comes into direct contact with the grung's skin must succeed on a DC 12 Constitution saving throw or become poisoned for 1 minute. A poisoned creature no longer in direct contact with the grung can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Standing Leap. Yorb's long jump is up to 25 feet and its high jump is up to 15 feet, with or without a running start.
Dagger. Melee or Ranged Weapon Attack: +5 to hit, reach 5 ft. or range 20/60 ft., one target. Hit:5 (1d4 + 3) piercing damage, and the target must succeed on a DC 12 Constitution saving throw or take 5 (2d4) poison damage.
Shortbow. Ranged Weapon Attack: +5 to hit, range 80/320 ft., one target. Hit:6 (1d6 + 3) piercing damage, and the target must succeed on a DC 12 Constitution saving throw or take 5 (2d4) poison damage.
Mesmerizing Chirr (Recharge). Yorb makes a chirring noise to which grungs are immune. Each humanoid or beast that is within 15 feet of the grung and able to hear it must succeed on a DC 12 Wisdom saving throw or be stunned until the end of the grung's next turn.