Arcanomagnetic Repulsion

2nd-level abjuration
Casting Time: 1 action
Range: Self (20-foot-radius sphere)
Components: V, S
Duration: Concentration, up to 1 minute
Class: Cleric, Druid, Sorcerer, Warlock, Wizard

You emit waves of arcanomagnetic energy, distorting the trajectories of ferrous items. For the duration, attacks using ferrous weapons or ammunition made against you have disadvantage. In addition, the area within 20 feet of you is difficult terrain for creatures that are made of ferrous metal or are wearing ferrous armour.

Magnetic Pulse. When you cast this spell and as a bonus action on your subsequent turns, you can force one Huge or smaller creature that is experiencing this difficult terrain to make a Strength saving throw. On a failure, it takes 1d6 force damage and is knocked prone.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the radius of the difficult terrain increases by 5 feet and the damage increases by 1d6 for each slot level above 2nd.

Source: Heliana's Guide to Monster Hunting