Magnetobolt

Evocation cantrip

Casting Time: 1 action
Range: 90 feet
Components: V, S
Duration: Instantaneous
Class: Druid, Sorcerer, Warlock, Wizard

A near-invisible pulse of arcanomagnetic energy shoots towards a creature within range. Make a ranged spell attack against the target. On a hit, the target takes 1d6 force damage and must succeed on a Strength saving throw or be knocked prone. A creature made of ferrous metal or wearing ferrous armour has disadvantage on this saving throw.

At Higher Levels. This spell’s damage increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).

Source: Heliana's Guide to Monster Hunting