void OnTriggerEnter(Collider collider)
    {
        if (collider.gameObject.tag == "enemy")
        {
            GameObject hitTemp = Instantiate(hitEffect, transform.position, Quaternion.identity);
            Destroy(hitTemp, 1);
            Destroy(collider.gameObject);
            towerHealth    -= 20;
            healthBar.value = towerHealth;

            if (towerHealth == 0)
            {
                StartCoroutine(EnemySpawn.WaitForRestart());
                gameObject.transform.localScale = new Vector3(0, 0, 0);
            }
        }

        if (collider.gameObject.tag == "boss")
        {
            GameObject hitTemp = Instantiate(hitEffect, transform.position, Quaternion.identity);
            Destroy(hitTemp, 1);
            Destroy(collider.gameObject);
            towerHealth     = 0;
            healthBar.value = towerHealth;
            StartCoroutine(EnemySpawn.WaitForRestart());
            gameObject.transform.localScale = new Vector3(0, 0, 0);
        }
    }