Heatstroke

(Spell Compendium, page 113, DnD 3.5)

Transmutation

Level: ; Druid 3
Components: V, S
Casting Time: 1 standard action
Range: Medium (100 ft. + 10 ft./level)
Target: One creature
Duration: Instantaneous
Saving Throw: Fortitude partial
Spell Resistance: Yes

With a wave of your hand and a few hissed words, you cause the target creature to suffer as if it had been toiling for hours on end under the merciless hammer of the desert sun.

If the target creature fails to resist the spell, it immediately becomes fatigued. If it is already fatigued, it instead becomes exhausted. The subject takes 2d6 points of nonlethal damage from the oppressive heat as well, even if it makes the Fortitude saving throw to avoid fatigue or exhaustion.

A creature wearing heavy armor takes a -4 penalty on its save. Creatures with immunity or resistance to fire are not affected by this spell.