"So you think you are cool?"; "I hope it is not too cold for you! HeHeHe."; "Freeze!".
She'll try to keep her distance, paralyze and spam you with attacks.
This creature fights much like a Necromancer, however doesn't summon, but paralyzes instead and have a tough armor. Be warned, if you're turned into a snowman your invisibility will be canceled. Ice Witch had 540 Hit points before Summer Update 2009. Ice Witches heal a lot, it could be a good idea to team with a mage to shoot Thunderstorms at groups. Since summer update 2009 all loot from this creature became rare drops, most witches you kill will be empty, so you'll be hunting for a while to get anything from them.