WereChihuahua

Shapechanger. The werechihuahua can use its action to polymorph into a Chihuahuah-humanoid hybrid or into a giant Chihuahua  or back into its true form, which is humanoid. Its statistics, other than its size, 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 Smell. The wererchihuahua has advantage on Wisdom (Perception) checks that rely on smell.

Maddening Bark:  Once per day, creatures in a 20 foot radius must make a Wisdom Saving Throw DC 16.  Creatures that fail the save suffer the effects of a Crown of Madness spell.

Shrill Bark:  Once per day, creatures within ear shot of the WereChihuahua, must make a Constitution Saving Throw DC 16.  A failed save means the creatures suffer 2d8 points of force damage. 

Multiattack (Humanoid or Hybrid Form Only). The werechihuahua makes two attacks, only one of which can be a bite.

Bite (Rat or Hybrid Form Only). Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 4 (1d4 + 2) piercing damage. If the target is a humanoid, it must succeed on a DC 11 Constitution saving throw or be cursed with werechihuahua lycanthropy (only when its Drow).

Shortsword (Humanoid or Hybrid Form Only). Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) piercing damage.

Hand Crossbow (Humanoid or Hybrid Form Only). Ranged Weapon Attack: +4 to hit, range 30/120 ft., one target. Hit: 5 (1d6 + 2) piercing damage.