One of Far Cry 5's best weapons is the Magnopulser, a strange artifact that lands in your lap after completing a series of quests with some wacky homebrew scientist named Larry. Seriously, don't ignore the sidequests—they contain some of the cheekiest rewards.
To find Larry, head to Holland Valley. He's located directly east of Fall's End at a location called Parker Laboratories. Go there, save the guy, and get to doing his chores for him.
He'll run you through some 'tasks' meant to aid his research, all of which make the conspiracy theorist look like he's onto something. We'll avoid getting into the details, but it's Far Cry so you're going to have to climb some towers and shoot some bad guys.
Complete the quests to receive the Magnopulser, Far Cry's deadly take on the Airzooka. It sends cultists flying and dissolves them at point blank. Try it on a friend—it won't hurt them, but you should still feel bad. I do. I'm haunted by this memory: