Mob. The mob takes up its entire space. Other creatures can enter the space, but a creature that does so is subjected to the mob’s Engulf and has disadvantage on the saving throw. Creatures inside the mob have three-quarters cover against attacks made from outside the mob. A creature within 5 feet of the mob can take an action to
pull a creature or object out of the mob. Doing so requires a successful DC 20 Strength check. If the target fails the check by 5 or more, it is pulled into the mob’s space and is subjected to the mob’s Engulf. The mob can hold only one Large creature or up to four Medium or smaller creatures inside it at a time. The mob can move through any opening large enough for a Medium zombie. The mob can’t regain hit points or gain temporary hit points.

Disband. If the mob is reduced to 0 hit points, four zombies
rise from its remains.

Slam. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 23 (4d6 + 9) bludgeoning damage.

Engulf. The mob moves up to its speed. While doing so, it can enter Large or smaller creatures’ spaces. Whenever the mob enters a creature’s space, the creature must make a DC 20 Strength or Dexterity saving throw (the target’s choice). On a successful save, the creature can choose to be pushed 5 feet back or to the side of the mob. A creature that chooses not to be pushed suffers the consequences of a failed saving
throw. On a failed save, the mob enters the creature’s space, and the creature takes 23 (4d6 + 9) bludgeoning damage and is engulfed. The engulfed creature is restrained and takes 37 (8d6 + 9) bludgeoning damage at the start of each of the mob’s turns.
An engulfed creature can try to escape by taking an action to make a DC 20 Strength or Dexterity check (the target’s choice). On a success, the creature escapes and enters a space of its choice within 5 feet of the mob.