Undead Fortitude. If the zombie start its turn with 0 hit points, it makes a DC10 Constitution saving throw, unless it took radiant damage or a critical hit since its last turn. On a success, the zombie gains 1 hit point. A zombie with 0 hit points is killed instantly if it is attacked.

Sudden Lunge. The zomie's attack have a reach of 10 feet for the purpoes of making opportunity attacks. When it makes an opportunity attack, it moves up to 5 feet towards its target as part of the attack.

Grasp of the Dead. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage. Instead of dealing damage, the zombie may grapple the target (escape DC 11).

Festering Bite. Melee Weopon Attack: +3 to hit, reacht 5 ft., targets one grappled creature. Hit: 4 (1d6 + 1) piercing damge and 7 (2d6) necrotic damage.