I've searched for this plug-in but I found nothing. The main idea is: to prevent aggresive mobs from spawning in certain areas, on difficulty higher than peaceful. You know what I mean right? I want to be able to mark area when I don't want monsters to spawn!
WorldGuard. /RG flag <region_name> mob-spawning deny; /RG flag <region_name> deny-spawn creeper, zombie, skeleton, etc.; /RG flag <region_name> mob-damage deny.
mar457 myrrdin777 You can also do it without any plugin and even in single player : /gamerule doMobSpawning false