This spell could affect one creature up to 40 yd (36.6 m) away. If the target had sufficient resistance to spells, then this spell failed with no ill effects. Otherwise, creatures of above average intelligence or wisdom were suddenly fatigued enough to cause them to delay their next action, hopefully giving the caster or the caster's allies an advantage. Creatures of below average intelligence or wisdom were overcome with exhaustion and vertigo, causing them to collapse immediately for one minute. After the spell wore off, the target recovered just as quickly.
This spell only affected creatures that normally sleep. Undead and elementals, for example, were immune.