Otiluke's Siege Sphere

This spell creates a large, boulder-sized sphere of force that can be fired by a catapult. The siege sphere lasts for one complete turn before it fades out of existence, so it must be fired within one turn of the spell's casting. The siege sphere can take several different forms, and the type of sphere to be created must be decided when the spell is memorized. The siege sphere is as hard as adamantite before it is launched, and can be destroyed only by a dispel magic, disintegrate, or wish. After the sphere is fired, it takes on a different form, depending on the type of the sphere created. Despite the form that the attack takes, Otiluke's siege sphere vanishes after its attack. Several different types of spheres are possible.

* Crystal Shards: This sphere splinters apart 30 feet above the ground, raining down crystal shards in a 20-foot radius circle. Each creature in the area takes 5d6 points of damage regardless of Armor Class.

: The material component is a pinch of sharp diamond flakes.

* Liquid Fire: When the sphere strikes, it instantly shatters, spraying a mass of liquid fire over an area 30 feet in radius. All combustibles in the area of effect are ignited. Any creature struck by the liquid fire takes 2d4 points of damage per round for 2d6 rounds unless the fire is doused or the burning fluid is washed off.

: The material components for this form are a drop of pitch, a bit of phosphorus, and a pinch of diamond dust.

* Wrecking Ball: Upon nearing its target, the sphere's density dramatically increases so it strikes with three times the impact (and damage) of a heavy catapult.

: The material components are a lodestone and a pinch of diamond dust.

Notes: Uncommon or rare spell (WoG).