Water mephits come from the Elemental Plane of Water.
Water mephits are jaunty creatures with an unflagging sense of humor who quickly get on the nerves of everyone around them. Each one is about 4 feet tall and weighs about 30 pounds.
Water mephits speak Common and Aquan.

Breath Weapon (Su): 15-foot cone of caustic liquid, damage 1d8 acid, Reflex DC 13 half. The save DC is Consitution-based and includes a +1 racial bonus.
Spell-Like Abilities: Once per hour a water mephit can hurl an acidic blob that functions like acid arrow (caster level 3rd). Once per day it can create a mass of smelly fog that duplicates the effect of a stinking cloud spell (DC 15, caster level 6th). The save DC is Charisma-based.
Fast Healing (Ex): A water mephit heals only if it is exposed to rain or submerged up to its waist in water.
Skills: A water mephit has a +8 racial 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.

---

System Reference Document -> List of Creatures (SRD)