I want to make an object appear randomly at the right hand side of the screen and then slide across the screen and disapear at the left hand side. I am working with libgdx. I have this bit of code but it makes items fall from the top down. Please help.

public EntityManager(int amount, OrthoCamera camera) {
    player = new Player(new Vector2(15, 230), new Vector2(0, 0), this, camera);
    for (int i = 0; i < amount; i++) {
        float x = MathUtils.random(0, MainGame.HEIGHT - TextureManager.ENEMY.getHeight());
        float y = MathUtils.random(MainGame.WIDTH, MainGame.WIDTH * 10);
        float speed = MathUtils.random(2, 10);
        addEntity(new Enemy(new Vector2(x, y), new Vector2(-0, -speed)));
    }