Amphibious. The grung can breathe air and water.   Poisonous Skin. Any creature that grapples the grung or otherwise comes in 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. The grung's long jump is up to 25 feet and its high jump is up to 15 feet, with or without a running start.