Wereduck

Shapechanger. The wereduck can use its action to polymorph into a duck-humanoid hybrid or into a duck, 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.

Keen Hearing and Smell. The wereduck has advantage on Wisdom (Perception) checks that rely on hearing or smell.

Multiattack. (All forms). The wereduck makes two attacks: two with its spear (humanoid form) or one with its bill and one with its slam (hybrid form).

Pierce(duck or Hybrid Form Only). Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 6 (2d8 + 2) piercing damage. If the target is a humanoid, it must succeed on a DC 12 Constitution saving throw or be cursed with wereduck lycanthropy.

Slam(Hybrid or duck Forms Only). Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 7 (2d4 + 2) bludgeoning damage.

Swallow (Duck form only) The duck makes one bite attack against a medium or small 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 duck, and it takes (5d4) piercing damage at the start of each of the duck's turns. The duck can have only one target swallowed at a time. If the duck dies, a swallowed creature is no longer restrained by it and can escape from the corpse using 5 feet of movement, exiting prone.