Can be enhanced with the Freeze spec, where at the end of the Frostbite Tower's channel it has a chance to freeze the target for 3 seconds. It is the only defense able to either slow or freeze enemies. It also is one of the rare defenses incapable of dealing any damage.
This tower has some invisible stats, such as the Chill Intensity (Defense Power) and Channel Rate (Defense Speed), both which are also affected by upgrading. By default, the Chill Intensity is a 50% speed reduction debuff.