Armour Of Lux

Cast on any creature you can see, Protective magical light surrounds the creature the spell is cast on. You gain 5 temp hp and your armour raises by 1 whilst the spell is in effect. It does not cost a recast to move from one player to another. 

Using a Higher-Level Spell Slot. The armour class raises by 2 and the temp hp rasises by 5 at level 11