No-Look Casting

You are skilled in the art of using your spells against large numbers of foes. When casting a spell with a to-hit roll, you may attempt to look at one target while aiming at another. The actual target must have been visible to you at the conclusion of your previous turn (or at the beginning of combat if this is round 1) and have not moved from that position since that time. The fake target must be visible and must be able to see you when the spell is cast. The fake target takes 1 d4 of AC penalty until the end of your next turn or until they are attacked. The attack to the true target is made with disadvantage (after all, you're not looking at it), but the target also rolls any save at disadvantage (it wasn't anticipating the damage).