Mob. The mob has the following traits.

• The mob has resistance to all damage that affects a single target, is vulnerable to AOE damage that effects part of the mob's space, and takes 3x damage from AOE effects that fully encompass the mob.
• The mob may move through other creature's spaces and end their turn there. While another creature is in the mob's space they are considered restrained. The creature may move with a DC 15 (mob's strength score) athletics check.
• The mob may not be subject to any conditions unless they specifically affect all creatures in an area.
• When the mob reaches 0 hit points, it breaks, and 2d8 zombies take its place. These survivors have 1 level of exhaustion, and are bloodied (1/2 health).
• The mob may not regain health or receive temporary hit points.

Mob Mentality. The mob has advantage on saving throws for the frightened condition, as well as effects that turn undead.

Multiple Creatures. The mob may take a reaction per turn, rather than per round.

Multiattack. The horde makes five slam attacks. This is reduced to four attacks at 150 hp, three attacks at 100 hp, and two attacks at 50 hp.

Slam. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 12 (3d6 + 2) bludgeoning damage and the target must make a DC 12 athletics or acrobatics check or be pulled into the swarms space.

Pile On. One target within 5 feet of the mob is attacked as dozens of zombies swarm them. The target must succeed on a DC 15 Strength save or be knocked prone and restrained. If the target is knocked prone, the mob may make 2 slam attacks with advantage. The target may use their action to repeat the saving throw, and is no longer restrained upon a success.