Amphibious. The frog can breathe air and water.

Standing Leap. The frog's long jump is up to 10 feet and its high jump is up to 5 feet, with or without a running start.

Acid Skin. Any creature that comes in contact with the frog's skin must make a DC 14 Constitution saving throw, on a failed save, the creature takes 4d6 acid damage and half as much on a success.

Multiattack. Acid frog can make two attacks in one turn. 

Tongue. The frog can attempt to grapple a creature with its tongue. The target must make a DC 15 Strength or Dexterity (GM's choice) saving throw and on a fail, the creature is grappled and takes 1d6 acid damage. The creature may repeat the saving throw on each of their turns. On a success, they are no longer grappled but on a fail, they take another 1d6 acid damage.

Acidic Spit. On its turn, the frog can use it's action to make a ranged attack and spit corrosive acid. It's a range of 10 ft./30 ft. and a +2 to hit. Dealing 3d8 acid damage and the target is now poisoned.

Slap. The frog can also make a melee attack with its front feet. It's +3 to hit and deals 2d8 bludgeoning damage and the target must make a DC 10 Constitution saving throw. On a failed save, the target takes 2d6 acid damage and half as mush on a success.