Trilobite SwarmCreature 3
Source Pathfinder Monster Core 2
Perception +9 (darkvision, wavesense (imprecise) 60 feet)
Languages none
Skills Athletics +8, Stealth +9, Survival +7
Str +1, Dex +4, Con +3, Int -5, Wis +2, Cha +0
AC 18; Fort +10; Reflex +9; Will +7;
HP 30
Speed 0 feet (swim 25 feet)
Immunities swarm mind, precision
Weaknesses Area Damage 5, Splash Damage 5
Resistances Bludgeoning 3, Piercing 3, Slashing 5
Clinging Bites
The trilobites in the swarm latch onto creatures and gnaw at them. Each enemy in the swarm's space takes 2d6 slashing damage (DC 18 reflex save).
Trilobites typically live in close proximity to others of their kind. On rare occasions, particularly when the most common prey around is larger than what a single trilobite can take down, they form swarms that seem to actively cooperate with each other. These swarms latch onto their prey, and the combined efforts of so many trilobites at once make escape difficult.
Often overlooked as little more than water-dwelling pests, trilobites are a varied class of arthropods found throughout the seas and oceans of Golarion. So ancient and widespread are these critters that trilobite fossils are as commonly found as living specimens. Trilobites vary wildly in both size and diet, with the largest reaching up to 28 inches long. Fossil record shows that trilobites were even more diverse and prevalent in ancient times than they are today, but their species entered a decline due to the devastation of Earthfall.
Traits
Anything that doesn't list another rarity trait (uncommon, rare, or unique) automatically has the common trait. This rarity indicates that an ability, item, or spell is available to all players who meet the prerequisites for it. A creature of this rarity is generally known and can be summoned with the appropriate summon spell.
AnimalAn animal is a creature with a relatively low intelligence. It typically doesn't have an Intelligence attribute modifier over –4, can't speak languages, and can't be trained in Intelligence-based skills.
AquaticAquatic creatures are at home underwater. Their bludgeoning and slashing unarmed Strikes don't take the usual –2 penalty for being underwater. Aquatic creatures can breathe water but not air.
SwarmA swarm is a mass or cloud of creatures that functions as one monster. Its size entry gives the size of the entire mass, though for most swarms the individual creatures that make up that mass are Tiny. A swarm can occupy the same space as other creatures and must do so in order to use its damaging action. A swarm typically has weakness to effects that deal damage over an area (like area spells and splash weapons). Swarms are immune to the grabbed, prone, and restrained conditions.