Languor

This spell causes creatures it hits to become weak and slow.

(Complete Divine)
Originally posted on D&D tools

Transmutation

Level: Druid 4,
Components: V, S,
Casting Time: 1 standard action
Range: Close (25 ft. + 5 ft./2 levels)
Effect: Ray
Duration: 1 round/level
Saving Throw: Will negates
Spell Resistance: Yes

A subject who fails a Will save is slowed as the spell and suffers a cumulative enhancement penalty to Strength equal to 1d6-1 per two caster levels (minimum additional penalty of 0, maximum of -10) each round. If the subject’s Strength drops below 1, it is helpless.

The spell’s slow effect counters and is countered by haste. However, the Strength penalty is not countered by haste.