Create tag in script, then check for it in collision

Questions & Answers
1

I’ve followed the Tutorial Project: Space Shooter, and now want to modify it so only certain asteroids give points. I’m trying to do this by giving the asteroids a tag, through scripting, after instantiating. Unfortunately the asteroids in the collider check with the lasers (“DestroyByContact”) the asteroids continue to have the tag “Untagged”. I’ve tried asteroid.tag, asteroid.collider.tag, asteroid.rigidbody.tag, …

From: GameController.cs

public IEnumerator SpawnWaves() {
	// ...
	while (true) {
		for (int i = 0; i < hazardCount; i++) {
			// ...
			GameObject asteroid = Instantiate (hazard, spawnPosition, spawnRotation) as GameObject;
			if (Random.value > 0.75f) {
				asteroid.tag = "MetalAsteroid";
				//Debug.Log("Spawned 1 point");
			}
			yield return new WaitForSeconds (spawnWait);
		}
		// etc...
	}
}

From: DestroyOnContact.cs

void OnTriggerEnter(Collider other) {
	int scoreValue = 0;
	if (other.tag == "Boundary") { // OK
		return;
	}
	if (other.tag == "Player") { // OK
		Instantiate (playerExplosion, other.transform.position, other.transform.rotation);
		gameController.GameOver ();
	}
	if (other.tag == "MetalAsteroid") { // Never gets called
		Debug.Log ("Shot 1 point");
		scoreValue = 1;
	}
	Debug.Log("Tag: " + other.tag); // Untagged when expecting MetalAsteroid
	Instantiate (explosion, transform.position, transform.rotation);
	gameController.AddScore (scoreValue);
	Destroy (other.gameObject);
	Destroy (gameObject);
}
2

I think you cannot give tag other than the one in the list. So you cannot just create one at runtime, you need to place it first in the list.