(Player's Handbook II)

Evocation [Death, Fire]
Level: Sorcerer 9, Wizard 9,
Components: V, S, M,
Casting Time: 1 standard action
Range: Medium (100 ft. + 10 ft./level)
Target: One creature
Duration: Instantaneous
Saving Throw: Fortitude partial; see text
Spell Resistance: Yes

The creature you point at explodes in a massive spray of fire.
If the target fails its saving throw, this spell slays the creature, and the explosion extends out to a 20-foot-radius burst around it.
Creatures in this area take 1d6 points of fire damage per caster level (maximum 20d6), though they can attempt Reflex saves for half damage.
The exploded creature's remains are scattered and vaporized, leaving nothing but dry ash.
If the target succeeds on its saving throw, it is wracked by a series of small explosions and takes 7d6 points of fire damage.
If this damage kills the creature, it explodes as described above.
Detonate has no effect on creatures that have immunity to fire.
Material Component: A tindertwig and a piece of string.