Piranha Swarm

Tiny Animal (Aquatic, Swarm)
Hit Dice:
4d8 (13 hp)
Initiative: +2
Speed: Swim 40 ft.
Armor Class: 15 (+2 size, +2 Dex, +1 natural), touch 14, flat-footed 13
Base Attack/Grapple: +3/-
Attack: Swarm (1d6)
Full Attack: Swarm (1d6)
Space/Reach: 10 ft./0 ft.
Special Attacks: Distraction, frenzied attack
Special Qualities: Half damage from slashing and piercing, low-light vision, scent, swarm traits
Saves: Fort +5, Ref +6, Will +3
Abilities: Str 2, Dex 14, Con 10, Int 1, Wis 14, Cha 2
Skills: Listen +7, Spot +6, Swim +10
Feats: Alertness, Weapon Finesse
Environment: Warm aquatic
Organization: Solitary or school (2–4 swarms)
Challenge Rating: 5
Treasure: None
Alignment: Always neutral
Advancement: None
Level Adjustment: -

The water bubbles with the thrashing of hundreds of fish just below the surface. Before your eyes, what was once a crocodile is stripped to a bare skeleton in a manner of seconds. Thankfully, the water becomes obfuscated by a cloud of blood, sparing you from having to watch the last of this frenzied feeding.

Piranhas are tiny fish with razor sharp teeth and an appetite for meat. While aggressive as a group, piranhas are harmful only to the smallest of creatures on the rare occasion they are encountered alone. Piranha swarms hunt up and down freshwater rivers. They are most often encountered in tropical locations, but occasionally a school becomes dislocated due to flood or drought changing the flow of their natural habitat.

Combat
Piranhas are the boldest of predators, attacking anything made of meat (living or dead) that enters their territory. Whether it’s a school of fish that swims too close or a human that falls from a boat, very little can stand up to a piranha swarm’s frenzied attack.

Distraction (Ex): Any living creature that begins its turn with a piranha swarm in its space must succeed on a DC 12 Fortitude save or be nauseated for 1 round. The save DC is Constitution-based.

Frenzied Attack (Ex): Any creature that ends its turn in a piranha swarm’s space takes 3d4 points of damage.Creatures killed by a piranha swarm are reduced to a bare skeleton, and therefore are not eligible to be brought back to life via raise dead.

Skills: A piranha swarm uses its Dexterity modifier instead of its Strength modifier for Swim checks. A piranha swarm has a +8 bonus on any Swim check to perform some special action or avoid a hazard. It can always choose to take 10 on a Swim check, even if distracted or endangered. It can use the run action while swimming, provided it swims in a straight line.