3-level Abjuration
You can set a magical trap by infusing explosive magic into an item. You can set this item to detonate when someone comes within 5 feet of it, or by a verbal command using your reaction (one or more mines can be detonated).
When the magic trap detonates, each creature in a 20-foot-radius sphere centered on the item must make a Dexterity saving throw. A creature takes 5d8 fire damage on a failed save, or half as much damage on a successful one. If a creature is in the area of effect of more than one fireburst mine during a turn, they take half damage from any subsequent effects of the mines.
A magical mine must be set 5 feet or more from another mine, and cannot be moved once placed; any attempt to move it results in it detonating unless the Artificer that set it disarms it with an action.