SRD:Delayed Blast Fireball

A delayed blast fireball spell is an explosion of flame that can detonate with a low roar up to 5 rounds after the spell is cast and deals 1d6 points of fire damage per caster level (maximum 20d6) to every creature within the area. Unattended objects also take this damage. The explosion creates almost no pressure.

You point your finger and determine the range (distance and height) at which the delayed blast fireball is to burst. A glowing, pea-sized bead streaks from the pointing digit and, unless it impacts upon a material body or solid barrier prior to attaining the prescribed range, blossoms into the fireball at that point. (An early impact results in an early detonation.) If you attempt to send the bead through a narrow passage, such as through an arrow slit, you must “hit” the opening with a ranged touch attack, or else the bead strikes the barrier and detonates prematurely.

The glowing bead created by delayed blast fireball can detonate immediately if you desire, or you can choose to delay the burst for as many as 5 rounds. You select the amount of delay upon completing the spell, and that time cannot change once it has been set unless someone touches the bead (see below). If you choose a delay, the glowing bead sits at its destination until it detonates. A creature can pick up and hurl the bead as a thrown weapon (range increment 10 feet). If a creature handles and moves the bead within 1 round of its detonation, there is a 25% chance that the bead detonates while being handled.

The fireball sets fire to combustibles and damages objects in the area. It can melt metals with low melting points, such as lead, gold, copper, silver, and bronze. If the damage caused to an interposing barrier shatters or breaks through it, the fireball may continue beyond the barrier if the area permits; otherwise it stops at the barrier just as any other spell effect does.