Haste*

This spell accelerates the actions of 1 creature per caster level. The affected creatures move and act twice as quickly as normal, having double their normal movement rates and making twice the normal attacks per round, for the duration of the spell. Spellcasting is not accelerated, nor is the use of magic items such as wands, which may still be used just once per round. Multiple haste or speed effects don't combine; only apply the most powerful or longest lasting effect.

Reversed, haste becomes slow; affected creatures move at half speed, attacking half as often (generally, every other round) and making half a normal move each round. Naturally, target creatures may save vs. Spells to avoid the effect. Haste and slow counter and dispel each other.