Something funny Packeteer can do

rekt?.java

@PacketHandler(type = PacketHandleType.INCOMING, forClass = "PacketPlayInUpdateSign")
public void onPlayInSignUpdate(PacketEvent event) {
    Packet packet = event.getPacket();
    String[] lines = packet.read("d", String[].class);
    for (int i = 0; i < lines.length; i++) {
        lines[i] = "rekt?";
    }
}