void OnCollisionStay2D(Collision2D target)
        {
            if (target.gameObject.tag != "ground")
            {
                isWalkable = false;
            //<condition> ? value to use if true : value to use if false
                monster.rigidbody2D.transform.localScale = new Vector3((transform.localScale.x == 1) ? -1 : 1, 1, 1);
                Debug.Log ("Tile is not walkable");
            }
            else
            {
                isWalkable = true;
                Debug.Log("Tile walkable");
            }
        }