Giant Frog is a Medium beast with unaligned alignment and Challenge Rating 1/4 in the 2024 SRD. This stat block includes AC 11, 18 hit points, speeds, traits, and actions.
Bite - Melee Attack Roll: +3, reach 5 ft. Hit: 5 (1d6 + 2) Piercing damage. If the target is a Medium or smaller creature, it has the Grappled condition (escape DC 11).
Swallow - The frog swallows a Small or smaller target it is grappling. While swallowed, the target isn’t Grappled but has the Blinded and Restrained conditions, and it has Total Cover against attacks and other effects outside the frog. While swallowing the target, the frog can’t use Bite, and if the frog dies, the swallowed target is no longer Restrained and can escape from the corpse using 5 feet of movement, exiting with the Prone condition. At the end of the frog’s next turn, the swallowed target takes 5 (2d4) Acid damage. If that damage doesn’t kill it, the frog disgorges it, causing it to exit Prone.