Chronomantic Zombie

Chronomantic Aura.

At the start of each creature’s turn within 10 feet of the zombie, that creature must succeed on a DC 16 Wisdom saving throw or be slowed until the start of its next turn (as if under the slow spell’s effects).

Temporal Resilience.

The zombie has advantage on Initiative rolls.

Undead Fortitude.

If damage reduces the zombie to 0 hit points, it must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage is radiant, force, or from a critical hit. On a success, the zombie drops to 1 hit point instead.

Undead.

The chronomantic zombie doesn’t require air, food, drink, or sleep.

Multiattack. The zombie makes two slam attacks.

Crushing Slam. Melee Weapon Attack: +10, reach 10 ft., one target.
Hit: 21 (3d10 + 6) bludgeoning damage plus 7 (2d6) necrotic damage.

Time-Rending Gaze (Recharge 5–6). The zombie targets one creature it can see within 60 feet. The target must succeed on a DC 16 Wisdom saving throw or take 27 (6d8) necrotic damage and lose its reaction until the end of its next turn. On a failure by 5 or more, the creature also ages 1d4 years (no mechanical effect unless the DM rules otherwise).