Steam Mephit

(from Planescape: Monstrous Compendium Appendix I - 1994):

Bossy and hypeisensitive, steam mephits are the selfappointed overlords of all mephits and, in their own minds, lords of the quasiplane of Steam. Mist mephits refuse to obey them, and this disobedience has led to a millennia-long rivalry between the types. 

In addition to the hissing steam that escapes from their pores, steam mephits leave a trail of near-boiling water where they walk. 

Combat: Unlike other mephits who delay attacking as long as possible, steam mephits, ruled by oversized egos, ambush even large, well-armed parties. They strike first with their boiling rainstorm, then concentrate their breath weapons on the nearest wizard or priest. 

The mephit’s two hardened claws cause ld4 damage each, plus 1 hp heat damage per touch. In addition, the victim is 50% likely to be stunned for one round. These effects are cumulative, so a victim raked twice could be stunned for two rounds. 

Steam mephits can breathe a scalding jet of water every other round with a 20’ range, automatically hitting one target (ld3 damage, with a 50% chance of stunning the victim for one round). 

Once per day a steam mephit can create a rainstorm of boiling water over a 20’x20’ area. This storm inflicts 2d6 damage to all victims in the area of effect. Steam mephits can also use putrefy food & drink (reverse of purify food and drink) once per day to contaminate water. 

Once per hour a steam mephit can attempt to gate in 1-2 other mephits (fire, magma, smoke, or steam). If two arrive, they are the same type. Steam mephits are immune to fire and heat damage. 

Ecology: Steam mephits heat confined areas or power small engines.

(From 3.5e Monster Manual I - 2003):

This winged creature looks like a miniature human with pale skin and wisps of vapor rising from its nose, mouth, and ears. It sheds drops of steaming water when it moves. 

Steam mephits come from the Elemental Plane of Fire. Steam mephits are bossy creatures who consider themselves the lords of all their kind. Each one is about 4 feet tall and weighs about 2 pounds. 

Steam mephits speak Common and Ignan. 

Combat: 

Unlike other mephits, steam mephits rush into combat eagerly, driven by an oversized ego. 

Breath Weapon (Su): 10-foot cone of steam, damage 1d4 fire, Reflex DC 12 half. Living creatures that fail their saves are tormented by burned skin and seared eyes unless they have immunity to fire or are otherwise protected. This effect imposes a –4 penalty to AC and a –2 penalty on attack rolls for 3 rounds. The save DC is Constitution-based and includes a +1 racial bonus. 

Spell-Like Abilities: Once per hour a steam mephit can surround itself with a plume of vapor, duplicating the effect of a blur spell (caster level 3rd). Once per day it can create a rainstorm of boiling water that affects a 20-foot-square area. Living creatures caught in the storm take 2d6 points of fire damage (Reflex DC 14 half; caster level 6th). This ability is the equivalent of a 2nd-level spell. The save DCs are Charisma-based. 

Fast Healing (Ex): A steam mephit heals only if it is touching boiling water or is in a hot, humid area.