People Swarms

For formations of enemy troops, panicked mobs and other large bodies of mooks I have decided that a swarm variant would be the best way to easily model large formations and allow a large number of raw recruits to still be a threat to powerful PCs. So, here comes the template.

Swarms are made up of unusually dense formations of creatures, usually hundreds in a space normally occupied by a few. Swarms can be size Huge (15x15), Gargantuan (20x20) or Colossal (30x30). Huge people swarms are usually composed of 20-40 individuals of small to medium size, packed into a space usually appropriate for only 9 such creatures. Gargantuan swarms are normally composed of 50-80 individuals in either a large and chaotic mob or a closely packed military formation. Colossal swarms would be composed of about 100-120 creatures in a tightly packed formation or a cramped crowd. For larger bodies simply use multiple swarms, so a crowd of thousands of rioters may be composed of dozens of colossal swarms.
Type: The swarm has the same type and subtype as the base creatures and gains the swarm subtype.
Hit Dice: For every 10 people in the swarm it has two HD. So Huge swarms have 4-8 HD, Gargantuan swarms have 10-16 HD, and Colossal swarms have 20-24 HD.
Hit Points: The swarm has average hit points for its hit dice and constitution.
Speed: As the base creatures, including adjustments for armor and encumbrance.
Defense: As the base creature. Do not adjust for swarm size. No matter how big the crowd you still have to hit the individual people in it.
Base Attack/Grapple: Base Attack as the base creatures adjusted for the new HD. Swarms can't grapple; these benefits are subsumed by the swarm attack and distraction special attack.
Attacks: People swarms may attack surrounding squares as the base creature and gain the swarm attack appropriate for their hit dice (see below).
Space/Reach: Space as a creature of the swarm's size, reach as the base creature. If weapons give extra reach with a "dead zone" inside it (such as a longspear) then the swarm is treated as having that reach without the "dead zone", representing the ability of people in the heart of the swarm to stab at targets inside the reach of those at the edges.
Traits: A people swarms gains the following traits.
Distraction (Ex): Any living creature that begins its turn within a people swarm in its space must succeed on a Fortitude save or be nauseated for one round. Save DC = 10 + 1/2 Swarm hit dice + Con modifier.
Swarm Attacks: A swarm automatically damages any creature(s) in its area at the end of its turn. No attack roll is needed and there is no miss chance for concealment or cover. The amount of damage is based upon the number of hit dice: 1d6 for every five hit dice, rounded up, to a maximum of 5d6.
Traits: A swarm has no clear front or back and no discernable anatomy so it is not subject to critical hits or flanking. (Comander variant: a people swarm can be given a leader that commands and directs it, thus giving it a 'discernable anatomy' either automatically or with an appropriate skill check [usually Spot, DC around 20], allowing Sneak Attacks and critical hits as the character specifically harms the commander or command group of the swarm.) Reducing a swarm to 0 hit points causes it to disperse. Likewise, a swarm rendered unconcious by non-lethal damage also disperses as the creatures are too tired to stay unified, when they have rested (and their non-lethal damage is again less than the swarm's hit points) they may reform into the swarm. Swarms are never staggered or reduced to a dying state, also they cannot be tripped, grappled, or bull rushed and they cannot grapple an opponent.
A swarm is immune to any spell or effect that targets a specific number of creatures (indcluding single-target spells), unless the swarm has an Intelligence score and a hive mind and it is a mind-affecting effect (charms, compulsions, phantasms, patterns, and morale effects). A swarms takes half again as much damage (+50%) from spells or other effects that affect an area, such as splash weapons, evocation spells, and some class abilities.