Foes of Serpentkind. The mongoosewere scores a Critical Hit if it on a 19 or 20 when making a melee attack against a serpentkind creature and serpentkind creatures have disadvantage on melee attacks against the mongoosewere. Serpentkind includes snakes, nagas, yuan-ti and similar creatures.​

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

Pack Tactics. The mongoosewere has advantage on an attack roll against a creature if at least one of the mongoosewere’s allies is within 5 feet of the creature and the ally isn’t incapacitated.

Shapechanger. The mongoosewere can use its action to polymorph into a Small or Medium humanoid, a mongoose-humanoid hybrid, or back into its true form (that of a mongoose). Other than its size, its statistics 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.

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

Bite (Mongoose or Hybrid Form Only). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 5 (1d8 + 1) piercing damage.

Shortsword (Humanoid or Hybrid Form Only). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) piercing damage.

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

War Dance. As an action, the mongoosewere cavorts and prances, dancing towards a creature within 90 feet (the war dance can not affect other mongooseweres). If the creature can see the mongoosewere, it must make a DC 12 Wisdom saving throw or be incapacitated for 1 minute, mesmerised by the mongoosewere's movements. Any other creature within range that see the war dance must make a DC 12 Wisdom saving throw with advantage or be incapacitated for 2 (1d4) rounds. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. The incapacitation also ends if the creature takes damage, or someone uses an action to shake or slap them awake. A war dancing mongoosewere can move up to 30 feet, but must move towards the creature targeted by its dancing.​