Dex's Magic Missile

You create 2 glowing darts of magical force. Each dart is sent toward a creature you can see within range. All darts are sent simultaneously, at one creature or several, but arrive at their targets in rapid succession. For each missile, make a ranged spell attack against the target. On a successful hit, the dart strengthens the target’s clothes or armor, and the target’s AC immediately increases by 1, for 1 minute (no concentration). A creature’s AC gained from this spell is lost if it is hit by this spell from a subsequent cast, but multiple successful hits from the same cast can stack.

At higher levels. When you cast this spell using a spell slot of 2nd level or higher, the spell creates one more dart for each slot level above 1st.