Frostball

Subzero, or frostball, is a powerful combat spell that creates a cloud of terrifying frost within radius up to 10 meters. Because of its unpredictable properties it is advised to use it only under the open sky, as in interiors it can spread towards the caster and their companions.

It is described as pretty useful against fiery dragons, but hardly noticeable by cryophilic creatures such as yeti or ice demons.