spawning a boss

Hello I've been working on this C# strip for last few days trying to figure out how to spawn 1 unit. I figured out how to spawn many units as a continuous loop but I don't know how to spawn just one unit at a Pacific time I'm hoping that there is someon

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class Spanwer : MonoBehaviour {
6.  
7.     public GameObject Enemy;
8.     public Transform[] spawnSpots;
9.     private float timeBtwSpawns;
10.     public float startTimeBtwSpawns;
11.  
12.     private void Start(){
13.         timeBtwSpawns = startTimeBtwSpawns;
14.     }
15.  
16.     private void Update()
17.     {
18.         if(timeBtwSpawns <= 0){
19.             int randPos = Random.Range(0, spawnSpots.Length);
20.             Instantiate(Enemy, spawnSpots[randPos].position, Quaternion.identity);
21.             timeBtwSpawns = startTimeBtwSpawns;
22.         }else{
23.             timeBtwSpawns -= Time.deltaTime;
24.         }
25.     }
26.  
27. }
28.  

e out there that could help me with this small issue any and all help is welcome.

 

Code (CSharp):

1. IEnumerable SpawningMachin()
2.     {
3.         while(true)
4.         {
5.             yield return new WaitForSecondsRealtime(2);
6.             Instantiate(Enemy, spawnSpots[randPos].position, Quaternion.identity);
7.         }
8.     }

Try IEnumerable

 

Or Invoke.

Code (CSharp):

1. public float timeBeforeSpawn; // will spawn this many seconds after start
2.  
3. void Start ()
4. {
5.     Invoke ("SpawnThing", timeBeforeSpawn);
6. }
7.  
8. private void SpawnThing ()
9. {
10.     Instantiate (Enemy, spawnSpots[randPos].position, Quaternion.identity);
11. }

 

Shouldn't the co-routine variant be:

Code (CSharp):

1. IEnumerable SpawningMachin()
2.     {
3.             yield return new WaitForSecondsRealtime(2);
4.             Instantiate(Enemy, spawnSpots[randPos].position, Quaternion.identity);
5.     }

Else it will repeat, rather than be a one shot.