if (o instanceof EnemyProjectile) {
EnemyProjectile p = (EnemyProjectile) o;
if (!projectileList.contains(p)) {
projectileList.add(p);
p.addObserver(this);
notifyObservers();
setChanged();
} else {
// The xCoord will be set to -1 when the Projectile goes off the screen. This will make sure it is properly removed from the map.