Concussion Bolt

You create a single glowing bolt of magical force. The bolt strikes a creature of your choice that you can see within range. It hits automatically. The bolt deals 8d8 Force damage to its target, with the victim being able to make a strength save to take half damage. If the victim fails their strength save, they are knocked prone. It can be blocked by a shield spell or a brooch of shielding or other magic that would stop a magic missile. This is an effective spell to use against a single foe with extremely high AC--e.g. a very powerful fighter with heavy armor--or against a distant foe the caster would rather not get in melee with.

Using a Higher-Level Spell Slot. The spell does an additional d8 of damage per level above 3rd.