Crowds and Mobs
One challenge I have had as a Game Master in the past is how to handle dense crowds or mobs in the game. The idea that people stick to the one person per five foot square in a mob just doesn’t work for more then one reason. There is also a serious slow down of the game when you have to run more then 6 creatures in an encounter. Lastly, the creatures that you want to use in mobs are just too weak to run as individuals in a mob and end up being killed quickly before they even have a chance to deal any damage.
This is more of a workshop article then a clear cut house rule post. I haven’t yet decided how to handle this but I wanted to walk through the process in a blog post so that GMs could see how I write my stuff. In the end I will conclude how I will handle mobs, but I also encourage people to take what is found here to come up with their own rules.
Someone (I want to say Monte Cook,) actually talked about this in an article found in one of the Kobold’s Guide to Game Design books. While I don’t have that book on hand, I do remember a few of the ideas he offered, and I have a few of my own as well.
- The rules about creatures occupying the same square don’t really apply to the creatures in the mob. Assume as many as four creatures per square if you need to know exactly how many are surrounding a character.
- The character’s square has enemies in it as well. The character is considered squeezing through a tight space for all of their actions.
- Movement is difficult due to shoving, poking, attacking, and resisting. Consider movement through the mob as difficult terrain.
- Casting spells is going to be difficult, the concentration DCs are increased by 10, are going to be as if the caster is grappled, or some special formula.
- A violent mob is going to attack viciously, from all sides, and will find weaknesses. Characters caught in the mob are going to take a set amount of damage each round no matter what their armor class is.
- Mobs can push, trip, grapple, and steal. Mobs should be able to use combat maneuvers.
- Mobs should be able to take attacks of opportunity.
- Mobs can take up any amount of space, from 5 foot squares to 50 foot squares, but they are not held to a square shape.
- Mobs can split up into different parts.
You know what this is sounding like? Swarms. You could just take a few of the ideas above and apply them to an encounter, making them part of the environment of the encounter instead of the creatures. I am going to just adapt the swarm subtype and create a mob type, making this all about the creatures in the mob. This means you can apply this to any humanoid creature to create a challenging mob for any level of of the game. With a little adjustment you could also turn this into stampede rules.
Here is how I would adjust the Swarm subtype into a Mob subtype (taken and adapted from d20pfsrd.com)
A mob is a collection of Small or Medium creatures that acts as a single creature. A mob has the characteristics of its type, except as noted here. A mob has a single pool of Hit Dice and hit points, a single initiative modifier, a single speed, and a single Armor Class. A mob makes saving throws as a single creature. A single mob occupies a square (if it is made up of nonflying creatures) or a cube (of flying creatures) 20 feet on a side. Even though the mob is Gargantuan sized, its reach is that of a Medium creature. In order to attack, it moves into an opponent’s space, which provokes an attack of opportunity. A mob can occupy the same space as a creature of any size, since it pushes around its prey. A mob cannot move through squares occupied by enemies if there are no free spaces on either side of the enemy. Enemies can move through mob squares, but the movement counts as difficult terrain and it provokes an attack of opportunity doing so.
A mob of small creatures consists of 8 nonflying creatures or 25 flying creatures per square. A mob of Medium creatures consists of 4 nonflying creatures or 15 flying creatures per square. Mobs of nonflying creatures include many more creatures than could normally fit in a 5-foot square based on their normal space, because creatures in a mob are packed tightly together when moving or attacking. Larger mobs are represented by multiples of single mobs. The area occupied by a mob is completely shapeable, though the mob usually remains in contiguous squares.
Traits: A mob has no clear front or back and no discernible anatomy, so it is not subject to critical hits or flanking. Reducing a mob to 0 hit points or less causes it to break up, though damage taken until that point does not degrade its ability to attack or resist attack. Mobs are never staggered or reduced to a dying state by damage. Also, they cannot be tripped, grappled, or bull rushed. A mob can grapple, trip, bull rush, overrun, or use any other combat maneuver they wish.
A mob is immune to any spell or effect that targets a specific number of creatures (including single-target spells such as disintegrate), with the exception of mind-affecting effects (charms, compulsions, morale effects, patterns, and phantasms) if the mob has a hive mind. A mob takes half again as much damage (+50%) from spells or effects that affect an area, such as splash weapons and many evocation spells.
A mob rendered unconscious by means of nonlethal damage becomes disorganized and dispersed, and does not reform until its hit points exceed its nonlethal damage.
Mob Attack: creatures with the mob subtype don’t make standard melee attacks. Instead, they deal automatic damage to any creature whose space they occupy at the end of their move, with no attack roll needed. Mob attacks are not subject to a miss chance for concealment or cover. A mob’s stat block has a “mob” in the Melee entries, with no attack bonus given. Mobs can take attacks of opportunity, following the entry in the stat block for attacks of opportunity.
The amount of damage a mob deals is based on the creature this template is given to. Take the main attack of the creature and multiply the number of damage dice by 4 for small creatures and 2 for medium creatures.
A mob’s attacks are nonmagical, unless the mob’s description states otherwise. Damage reduction sufficient to reduce a mob attack’s damage to 0, being incorporeal, or other Special Abilities usually give a creature immunity (or at least resistance) to damage from a mob. Some mobs also have acid, blood drain, poison, or other special attacks in addition to normal damage.
Mobs do not threaten creatures, and do not make attacks of opportunity with their mob attack. However, they distract foes whose squares they occupy, as described below.
Mobs possess the distraction ability. Spellcasting or concentrating on spells within the area of a mob requires a caster level check (DC 20 + spell level). Using skills that involve patience and concentration requires a DC 20 Will save.
Adapting a creature into a mob is like adding a template by using the following process:
The Mob template is an acquired template that can be added to any corporeal humanoid creature size Small or Medium with an intelligence of 3 or higher.
CR +4 (I have to be honest, I haven’t figured this out yet.)
Size and Type: The mob becomes Gargantuan sized and takes up the entire area of its space. The type stays humanoid but the mob subtype is added to the base creature.
Armor Class: The mob takes a -4 size penalty to its armor class.
Hit Dice: If the base creature is Small, it has a number of Hit Dice equal to the base creature multiplied by 20. If the base creature is Medium, it has a number of Hit Dice equal to the base creature multiplied by 16. Do not recalculate the Base Attack Bonus or saves based on these new Hit Dice.
Defenses: The base creature gains all of the immunities and resistances of a Mob. They also gain all of the vulnerabilities.
Speed: Same as base creature -10.
Attacks: Remove all attacks listed and replace them with the Special Attacks below.
Special Attacks: They gain the mob attack special attack. This attack has no attack bonus and the damage is equal to the base creatures main attack plus two additional damage dice. They also gain a separate entry for attacks of opportunity. The attack bonus is equal to the base creatures main attack +8, and the damage is equal to the main attack with one additional damage die.
Abilities: Str +2, Dex -2, Con +2
Saves: Fort +2, Ref -4, Will +4
Feats: A mob gains the Alertness and Combat Reflexes feats as bonus feats.
With these rules, you can now create mobs of kobolds, goblins, orcs, or any other humanoid creature that can challenge mid and high level characters. Go ahead and test them out, comment on them, and let me know how you feel this idea can be adjusted.