private void OnTriggerEnter2D(Collider2D collision) { Astronaut a = collision.gameObject.GetComponent <Astronaut>(); if ((a != null) && (a.Alive)) { if (!BossToActivate.hasbeenintroduced) { BossToActivate.introduceBoss(); foreach (Collider2D c in InvisibleColliders) { c.enabled = !c.enabled; } } } }