This magic item was taken from the future by a crazy mage who badly wanted to see the age of dinosaurs, not realizing that he was taking his lifetime supply of batteries with him. However they were found by an other mage who found that they are electric in water.

As an action, you can throw a battery 20 Ft. into a source of water. This deals [roll]1d4[/roll] lightning damage to everyone in the water within a 5 Ft. radius. After that, the AAA battery is empty and can't be used again. Instead of throwing a battery into water, you can throw it at an elemental that is composed of water, dealing [roll]1d6[/roll] damage instead of the normal 1d4. Alternatively, you can throw more batteries into the water for more damage as part of the same action, at a rate of one more dice for 1 more dice, up to six dice. 

Notes: Damage: Lightning, Damage: Lightning