Undead Behemoth

Undead Fortitude. If damage reduces the zombie to 0 hit points, it must make a Constitution saving throw with a DC of 3 + the damage taken, unless the damage is radiant or from a critical hit. On a success, the zombie drops to 1 hit point instead.

Curdling Scream: As an action the Behemoth can let out a loud scream heard from upto 60 ft away. DC 16 WIS check or be frightened until the end of your turn.

Multiattack. Can attack three times per turn. Unarmed attack: +8 to hit, reach 10 ft., one target. Hit: 14 (2d10 + 4) bludgeoning damage.

Call the Army: As a bonus action the Behemoth can forgo one of its attacks to have an ally undead attack for it. Works up to 30 ft away.

Hard to Leave: As a reaction when someone runs from their area, instead of one attack it can use two.