20 years ago, here in FL, on a fishing boat with a buddy, coming back from the intercoastal. Dusk. River maybe 70 feet wide. We idle past a park, other side of the small river, inhabited by ferals having a party.
The water around us started splashing, as objects thrown by the ferals homed in on us. Large rocks, size of your fist. Some larger. Picked up from the crumbled seawall boundary of the park and launched at us.
I moved to hammer the throttle, but my buddy already had the flare gun out. Shot a flare at them, skipped it off the water (on purpose), skimmed at them head high. They hit the deck, and ran screaming like banshees.
I laughed for 10 minutes.
My first thought was of using flares in naval warfare.
If the park had been full of pine needles and autumn leaves!
I laughed for 10 minutes
….i would call that “Effective “.