A pointed vial with runes etched into the glass spiralling down the body.  Within the vial a strand of flickering lightning is anchored to the point at the bottom of the vial, arcing toward the stopper, which is secured by a wire cage.

A creature may use an action to remove the stopper, causing lightning to streak from the vial in the direction it is pointed to a target up to 120 feet away. The target must make a DC 16 Dexterity saving throw, taking [roll]8d6[/roll] lightning damage on a failed save, or half as much damage on a successful one. The lightning then explodes out from the target striking the 3 closest creatures within 30 feet of the target, these creatures must also make a DC 16 Dexterity saving throw, taking [roll]4d6[/roll] lightning damage on a failed save, or half as much damage on a successful one.