public static Entity createBullet(World world, float x, float y, float angle, Entity shooter) {
Entity e = world.createEntity();
world.getManager(GroupManager.class).add(e, "bullets");
Transform transform = new Transform(x, y, angle);
e.addComponent(transform);
e.addComponent(new SpatialForm("bullet"));
e.addComponent(new Expiration(1500));
Body b = new Body(new Box(10, 10), 0.2f);
b.setUserData(e);
b.addExcludedBody(shooter.getComponent(Physics.class).getBody());