Delayed Detonation

As an action, you hold a small, metallic object in your hand such as a ball bearing, caltrop or cog and imbue it with concentrated, destructive energy. As part of the action, you may throw the object up to 50 feet away. 

At the beginning of your next turn, the energy in the object detonates, causing 1d6 force damage to all creatures within 5 feet of the object.

Enemies with a passive perception equal or superior to your spell save DC will spot the object and may choose to knock it away as an action, at a distance equal to their strength score * 3 in feet.

This cantrip's damage increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).