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;
	}

Firstly, make sure that var “health” is not static.
Also, please post fragments where you kill you enemy:)