Explosive Cascade

Evocation [Fire]
Level: Sorcerer 4, Wizard 4,
Components: V, S, M,
Casting Time: 1 action
Range: Close (25 ft. + 5 ft./2 levels)
Effect: 1-ft.-radius sphere
Area: One 5-ft.-square/level, all of which must be connected in one continuous path (S)
Duration: Instantaneous
Saving Throw: Reflex half
Spell Resistance: Yes
Material Component: Bat guano, sulfur, and copper packed into a metal tube with one closed end
Source: Magic of Faerun

You cause a bright ball of flame to bound and skip across the battlefield, damaging targets within its area.

The area is the path of the flame, and it deals 1d6 hit points of fire damage per caster level (maximum 10d6) to all creatures and objects within its area.
The flame lights up the area as if it were a torch. Small sparks and decaying flames remain in the area for 1 round, shedding light as candles but dealing no damage. If the damage from the flame destroys an interposing barrier, the flame can move beyond the barrier if it has not reached its maximum area.