I'd like to throw hordes of rampaging baboons against the players in my current game. Looking over the rules, the swarm subtype doesn't allow Small creatures, but the troop subtype seems to fulfill a similar role.
Some of the mechanics here are inspired by gibberlings from the Forgotten Realms.
My biggest question is whether CR 8 seems appropriate. The hit points are a little high, but the AC and damage are low, and a baboon horde doesn't have any magical abilities.
XP 4,800
N Small animal (troop)
Init +6; Senses low-light vision; Perception +17
DEFENSE
AC 15, touch 14, flat-footed 12 (+1 natural, +2 Dex, +1 dodge, +1 size)
hp 121 (22d8+22)
Fort +16, Ref +17, Will +10
Immune troop traits, mind-influencing effects
Weaknesses troop traits, fear of fire
OFFENSE
Speed 30 ft.
Melee troop (5d6 plus grab and trip)
Space 20 ft.; Reach 5 ft.
Special Attacks screech, grab (Gargantuan)
STATISTICS
Str 12, Dex 15, Con 12, Int 2, Wis 12, Cha 5
Base Atk +16; CMB +16 (+20 grapple); CMD 28
Feats Alertness, Blind-Fight, Dodge, Great Fortitude, Improved Initiative, Iron Will, Lightning Reflexes, Mobility, Skill Focus (Climb, Perception, Acrobatics)
Skills Acrobatics +15, Climb +14, Perception +17
SPECIAL ABILITIES
Screech (Ex)
A horde of screeching baboons makes a tremendous cacophony of screams, wails, hoots, and other sounds. Any creature who can hear this noise automatically takes a –2 penalty on all concentration checks.
In addition, all creatures who hear the screaming must make a Will save (DC 18) or become shaken for as long as the noise continues. Creatures who make their Will save are immune to this effect for 24 hours. The save DC is Charisma-based.
Fear of Fire (Ex)
A horde of screeching baboons that takes damage from fire must make a Will save (DC 20) or cower for 1 round.
ECOLOGY
Environment warm forest
Organization solitary, mob (2–4), or frenzy (5–15)
Treasure none
Sometimes baboons will congregate into huge herds tearing across the landscape and devouring everything in their path. Baboons in such a horde work themselves into a frenzy, and attack any living creature they see. Only magic or a barrier of fire can stop the advance of a screeching baboon horde.
A single screeching baboon horde consists of 30-40 individual creatures, but they move and attack as a unit.