Arcane shield

You summon an arcane shield that raises your AC with 5 including against the triggering attack, and you take no damage from magic missile. On your turn as an action you can send the shield flying to a target within range. Make a ranged spell attack, on a hit the shield does 6d8 force damage. If you choose to not throw the shield it stays for one more round until the beginning of your next turn, but the shield will then disappear.