Ring of Ice

What exactly does this Wolfen Lonewolf spell do? Does it just sometimes cancel damage from only missile attacks or possibly mitigate damage on strikes? I haven't noticed it doing anything when it is cast on a unit.

Chance of avoiding some range attacks, maybe.

Can work against the valkyrie's "100% chance to hit", but it's only a 50% chance on a caster that has very little mana regen...

Hopefully I go up against an all missile squad soon so I can test it.