public class Spawner : MonoBehaviour
{

public GameObject EnemyPrefab;
public float respawnTime = 260;


void Start()
{

}

void Update()
{
    if (respawnTime <= 0)
    {

        Instantiate(EnemyPrefab);

        respawnTime = 260;
    }
    else
    {
        respawnTime = respawnTime - 1;
    }
}