Here's an idea for a mage item!

Item X +80 AP +250 mana +25 Armor +10% CDR

Projected final cost 2800 - 3000 gold

Upon taking damage that would reduce maximum health below 30%, generates a shield that shields for 70 + 50% AP, (90 sec cooldown) and gives a flat 40 AP bonus until out of combat.

Is this too overpowered ;-;

EDIT: Buildpath is Glacial Shroud and NLD + unknown value of gold.