So the damage on it is way too high. The base and the scaling. For a Passive this thing can do 1000s of damage.
I played with the new DH and was getting Triple kills just by killing one person (or even just having them die near me)
I would suggest that you change it so anything that dies near Lissandra where she did 50%+ of the damage is turned into a Ice Statue, remove the moving toward things, up the slow to 30% and the AOE damage is 10% the targets max HP + 0.2 AP. Make the AOE size based of the size of the target but the current size for champions. That way minion waves would not pop just from killing one minion.