Wikia

Cripple
Cripple 30 yds. range 30 sec cooldown 210 Mana Instant Cripples the target, reducing movement speed by 20%, increasing time between melee and ranged attacks by 20%. Lasts 20 sec.
Usable by
Class	Warlock
Pet	Doomguard
Properties
Type	Offensive
School	Shadow
Cooldown	30 sec
Other information
Ranks	1
Related debuff
Magic Cripple Movement speed reduced by 40%. Time between melee and ranged attacks increased by 45%. Duration: 20 sec

Cripple reduces the melee, ranged, and movement speed of its opponents.

Notes

The movement speed reduction does not affect targets which are immune to movement slowing effects.

A variation of this ability was proposed to be a new warlock ability in the Wrath of the Lich King expansion, but was later dropped.

Hotfix (2009-05-13): "The Doomguard's ability Cripple now reduces ranged and melee attack speed by 20% instead of 45%. Cripple's slowing effect does not stack with other slowing effects such as Thunderclap and Infected Wounds."
Patch 1.6.0 (12-Jul-2005): Targets that are immune to movement slowing effects will no longer be affected by Cripple's movement slowing effect. Melee and ranged attack speed slowing effects will still affect these targets.