Vridi's astral haze

As an action the user cast releases a cyan mist from their hands or weapon.  The user then covers a willing creature they can see in the mist that creature roll as 1d4  and add it to their AC for the spells duration. 

At higher levels 

For each level higher than 1st you can cast the mist on another creature.

At 4th level you add 1 to the the roll