@Override
    public void collided(Sprite s1, Sprite s2) {

      damage = s1.getID();
      health = s2.getID();
      s2.setID(health - damage);
      s1.setID(damage - health);

      s1.setActive(false);

      if (health - damage < 1) {
        s2.setActive(false);
        game.setMoney(game.getMoney() + 10);
      }

      getGroup1().removeInactiveSprites();
      getGroup2().removeInactiveSprites();
    }