Shapechanger. The werefrog can use its action to polymorph into a frog-humanoid hybrid or into a giant frog, or back into its true form, which is humanoid. Its statistics, other than its AC, are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

Amphibious. The werefrog can breathe air and water.

Standing Leap. The werefrog's long jump is up to 20 feet and its high jump is up to 10 feet, with or without a running start.

Bite (Frog or Hybrid form only). Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) piercing damage, and the target is grappled (escape DC 11). Until this grapple ends, the target is restrained, and the frog can't bite another target. If the target is a humanoid, it must succeed on a DC 10 Constitution saving throw or be cursed with werefrog lycanthropy.

Swallow (Frog form only). 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 werefrog's turns. Any creature reduced to 0 hit points by this acid damage is permanently transformed into a frog, who is immediately spat out. This transformation can only be undone by wish or divine intervention. The werefrog can have only one target swallowed at a time. If the werefrog dies, a swallowed creature is no longer restrained by it and can escape from the corpse using 5 feet of movement, exiting prone.