Bellicose: Having or showing a ready disposition to fight. As in, "The old geezer certainly was angry when he noticed me walking my dog on his lawn, and he became downright bellicose when Mr. Wiggles answered nature's call a moment later. We almost got into a fistfight over some errant dog poop!"
RIP, Wiggles the rabbit. You live on forever by becoming a good dog name for my sample sentence.