A crackling, spherical storm cloud flies in whichever direction you point and deals electricity damage to those it strikes. It has a fly speed of 20 feet with perfect maneuverability. If it enters a space that contains a creature, the storm stops moving for the round and deals 3d6 points of electricity damage to that creature, though a successful Reflex save negates that damage. It provides concealment (20% miss chance) to anything within it, and its flickering light illuminates the same area a candle would.
The sphere moves as long as you actively direct it (as a move action for you); otherwise, it stays at rest and crackles with lightning. It can be moved by wind effects and counts as a Small creature for the purpose of determining how winds affect it. The sphere has no physical substance and cannot exert any force on corporeal creatures or objects. It disperses if it exceeds the spell’s range.