How can I acces the script of an object that I triggered?

Hello, I am working at a projectile script. The thing is that I want to be able to modify the health var from my enemy instance when the projectile triggers it. I want my projectile script to tell the enemyScript how much damage it should apply. So the real question is: "How on the earth can I acces only the script of that object? I have a lot of objects of the same type, so I need to acces the script of that triggered one. I will show you my scripts. Right now, my problem is that when I shot the first enemy that spawned it will kill only that instance and then if I continue shoting in the spawing order will works just fine. But if I shot the second spawned enemy, it will kill the first instance spawned. I am stuck, I need help!

Thank you very much!

Projectile.cs (Fragment)

 public EnemyBasics enemyController;

 void OnTriggerEnter2D(Collider2D col)
     {
         Debug.Log ("Collision");
         if(enemyFire)
         {
             if(col.gameObject.tag == "Player")
             {
                 PlayerController.OnDamageTaken(baseDamage);
                 collider2D.enabled = false;
             }
         }
         else
         {
             if(col.gameObject.tag == "Enemy")
             {
                 enemyController = col.gameObject.GetComponent<EnemyBasics>();
 
                 if(critChance > 0)
                 {
                     int random = Random.Range (0, 100);
                     if(random <= critChance)
                     {
                         outputDamage = baseDamage + bonusDamage + criticalDamage;
                     }
                 }
                 else
                 {
                     outputDamage = baseDamage + bonusDamage;
                 }
                 enemyController.OnDamageTaken(outputDamage);
             }
         }
     }

EnemyBasics.cs

 public void OnDamageTaken(float damage)
     {
         health -= damage;
     }