Buy a good quality Cat costume, trick or treat him with a basket of cat shit. put an add in the paper that he wants to take in all stray cats that cant find a good home, if he doesnt like it tell the cops he pointed the firearm at you, Call homeland security that you suspect he is makeing bombs and planning cat-tastrafies...

Just buy a bottle of good rum, two glasses and knock on his door, invite him for a drink and work the solution of the problem out in a neighbourly way, if he won't come to the party then call the news papper and give them a good story for the paper, with a photo of a crying kiddie who just had her cat killed by a gun toteing mad man.