Classic Strahd Zombie

Turn Resistance. The zombie has advantage on saving throws against any effect that turns undead.

Fearsome Visage.  Each creature of the zombie’s choice that is within 30 feet of the zombie and aware of it must succeed on a DC 11 Wisdom saving throw or become frightened for 1 minute. If the creature recognizes the zombie as someone they once knew (DM’s choice) the save is made with Disadvantage. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to all Strahd Zombie's Fearsome Visage for 24 hours. 

Loathsome Limbs. The zombie’s severed head and arms can continue to move. The arms move by clawing or wriggling like worms, while the head rolls around or hops by snapping its jaws. They can attack independently from the body once severed.

The first time a creature who dismembered the zombie sees the severed limbs moving to attack, they must succeed on another DC 11 Wisdom saving throw or become frightened until the end of their next turn. This time with advantage for having already stood their ground against the foul creatures.

Whenever the zombie takes at least 5 bludgeoning or slashing damage at one time, roll a d20 to determine what else happens to it:

1–8: One leg is severed from the zombie if it has any legs left.

9–16: One arm is severed from the zombie if it has any arms left.

17–20: The zombie is decapitated.

If the zombie is reduced to 0 total hit points, all body parts cease to move and attack. Until then, a severed part acts on the zombie’s initiative and has its own action and movement. A severed part has AC 8. Any damage it takes is subtracted from the zombie’s hit points.

A severed leg is unable to attack and has a speed of 5 feet.

A severed arm has a speed of 5 feet and can make one claw attack on its turn, with disadvantage on the attack roll. Each time the zombie loses an arm, it loses a claw attack.

If its head is severed, the zombie body loses its bite attack and its body is blinded unless the head can see it. The severed head has a speed of 2.5 feet (it can reach another square using its movement and its action to move). It can make a bite attack, but only against a target in its space.

The zombie’s speed is halved if it’s missing a leg. If it loses both legs, it falls prone. If it has both arms, it can crawl. With only one arm, it can still crawl, but its speed is halved. With no arms or legs, its speed is 0 feet, and it can’t benefit from bonuses to speed.

Communicate with Strahd. While in Barovia, the zombie can report the status of an assigned task back to Strahd. It takes a round to establish a connection with Strahd and it can only communicate success or failure.

Voice of the Master. Once the zombie has communicated successfully with Strahd, if he so chooses, Strahd can take full possession and speak and act through the zombie using its statistics; with the exception of Strahd's Intelligence [20 (+5)], Wisdom [15 (+2)], and Charisma [18 (+4)] scores. The possession lasts until either the body drops to 0 hit points, Strahd ends the possession as an action, or Strahd is forced out of the body by an effect such as the dispel evil and good spell.

Multiattack. The zombie makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 3 (1d4 + 1) piercing damage.

Claw. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 1) slashing damage.