Evocational Armor

You have an element streched across your body for ten minutes. during this period of time, you have 2+ to your armor class, and if someone fails a melee attack on you, chose one from following effects:

-10 (3d6) fire damage

-10 (3d6) acid damage

-10 (3d6) lightning damage

-10 (3d6) poison damage

-10 (3d6) cold damage

Once you chose one damage type, during the duration every time a creature missed you, that will be the following effect.