Lightning Elemental, Small
This creature looks like a dark storm cloud, with sparks suggesting eyes and long sweeping arms charged with bolts of lightning.

Small Lightning Elemental (CR 1; XP 400)
N Small outsider (air, elemental, extraplanar)
Init +6; Senses darkvision 60 ft.; Perception +5
AC 14, touch 13, flat-footed 12
(+2 Dex, +1 natural, +1 size)
hp 11 (2d10)
Fort +3, Ref +5, Will +0
Immune electricity, elemental traits
Speed fly 100 ft. (perfect)
Melee slam +5 (1d4 plus 1d3 electricity)
Special Attacks metal mastery, spark leap
Str 10, Dex 15, Con 10, Int 4, Wis 11, Cha 11
Base Atk +2; CMB +1; CMD 13
Feats Improved Initiative, Weapon FinesseB
Skills Acrobatics +7, Escape Artist +6, Fly +12, Knowledge (planes) +1, Perception +5
Language Auran
Special Abilities
Metal Mastery (Ex) A lightning elemental gains a +3 bonus on attack rolls if its opponent is wearing metal armor, is wielding a metal weapon, or is made of metal (such as an iron golem).
Spark Leap (Ex) A lightning elemental gains a +10 bonus on bull rush, disarm, overrun, and trip attacks when it charges a creature against whom its metal mastery ability applies.
Environment planes (Realms Within)
Organization solitary, pair, or gang (3–8)
Treasure none

Though most think of the Plane of Air as a vast expanse of clear sky, that plane also holds the power of the storm, including monstrous hurricanes larger than entire worlds and thunderstorms whose peals and claps can shatter stone. Whether lightning elementals are the by-product of common air elementals spending too much time near these electrically charged storms or are merely calved off like forgotten flurries, they are aggressive and almost suicidal in their willingness to leap into battle. They particularly enjoy attacking creatures that are made of metal and creatures that wear metal armor or wield metal weapons.

Many lightning elementals have a roughly humanoid shape, but some prefer animalistic shapes (particularly birds and dragons), and a few appear to be nothing more than large disembodied heads made of dark clouds with flickering lightning tongues. Regardless of the shape a lightning elemental takes, the air around the creature hums and throbs with the promise of electrocution and the tangy stink of ozone.