Bite

_Melee Weapon Attack:_ +4 to hit, reach 5 ft., one creature. _Hit:_ 5 (1d6+2) piercing damage, and the target is grappled (escape DC 12). Until this grapple ends, the target is restrained, and the frog can't Bite another target.

Swallow

The frog makes one Bite attack against a Small or smaller target it is grappling. If the attack hits, the target is swallowed, and the grapple ends. The swallowed target is blinded and restrained, it has total cover against attacks and other effects outside the frog, and it takes 5 (2d4) acid damage at the start of each of the frog's turns. The frog can have only one target swallowed at a time. If the frog takes any damage from the swallowed creature, the frog must succeed on a DC 10 CON save at the end of that turn or regurgitate the creature, which falls prone in a space within 5 feet of the frog. If the frog dies, a swallowed creature is no longer restrained by it and can escape from the corpse using 5 feet of movement, exiting prone.