How to get Acid Pistol?

In order to get research of the Acid pistol you need to kill the Overlord – a giant monster that sometimes attacks your base. You need to attack him while he stands on your base and defeat him in battle. 

Please note that killing Overlord with your turrets after he moves on to attack your buildings himself will not unlock this research. 

If you have any questions,
you can submit a ticket to the technical support team.