Season of Ice

+12% to Cold Damage over Time Multiplier
20% increased Effect of Chill [1]

Unpredictable Offensive was a notable passive skill.

Anointment

Blight anointment to unlock the passive:

Oil #1	Oil #2	Oil #3	Outcome
Indigo Oil	Black Oil	Golden Oil	Season of Ice	+12% to Cold Damage over Time Multiplier 20% increased Effect of Chill

Version	Changes
3.16.0	Unpredictable Offensive is removed from the game. Existing item anointed with that passive would have new passive Season of Ice instead.
3.11.0	Many passive skill clusters offered the same thing as other clusters, with the only differences being the location on the tree and the number of passive skills in the cluster. We also wanted to reduce the power of some clusters that were overly efficient, and increase the power of clusters that were inefficient. (Not in patch notes):^[1] Now grants 30% chance to Avoid being Stunned while Channelling (up from 20%).
3.7.0	Introduced to the game

↑ Bex_GGG (June 17, 2020). "All Notables and Keystones in Path of Exile: Harvest". Official Path of Exile forums. Retrieved November 5, 2021.