Wereghast

Grappler. While a creature is grappled by the Wereghast, the Wereghast has advantage on attack rolls against grappled targets, and the target takes an additional 3 1d6 damage whenever it is hit with the werewolf’s bite or claw attack.

Turning Defiance. The ghast and any ghouls within 60 feet of it have advantage on saving throws against effects that turn undead.

Stench. Any creature that starts its turn within 5 feet of the ghast must succeed on a DC 12 Constitution saving throw or be poisoned until the start of its next turn. On a successful saving throw, the creature is immune to the ghast's Stench for 24 hours.

Multiattack. The werewolf ravager makes two melee attacks. It can only make one bite attack per turn.

Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 12 (2d8 + 3) piercing damage. The target must succeed on a DC 14 Strength saving throw or be grappled.

Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 10 (2d6 + 3) slashing damage. If the target is a creature other than an undead, it must succeed on a DC 13 Constitution saving throw or be paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Skirmisher. The Wereghast can use it's reaction upon a missed strike to move up to half of it's movement. This does not provoke opportunity attacks.

End of Round 1: The Wereghast begins to mutate. Bones cracking, matted ugly fur growing from odd places in it's body, it doesn't stop attacking.

End of Round 2: The Wereghast transforms entirely, gaining 25 Temp HP, and gaining +1 to AC.