How to destroy GameObject's script(s)?

Mattsson almost completed the question. In C# i would...

 OnTriggerEnter(Collider other)
 {
      //assuming your bullet is tagged as bullet and the enemy has no health.
      if(other.gameObject.tag == "bullet")
      {
           Destroy(GetComponent<EnemyAI>());
      }
 }

Put this on the same object that the EnemyAI script is!

You can use GetComponent() for many things as shown here: http://docs.unity3d.com/ScriptReference/GameObject.GetComponent.html

Hope This Helps! =D

If you're making the destroy call from the EnemyAI:

 Destroy(this);

If you're doing it from some other object:

 //C# version
 //assumes you have a GameObject variable named "enemy" which is NOT null
 Destroy(enemy.GetComponent<EnemyAI>());

 //JS version
 Destroy(enemy.GetComponent(EnemyAI));

It's impossible to give more detail without knowing more about your scripts. If you can tell us more about your setup, we might be able to give a more specific answer.

In general, though, you should probably look up GetComponent tutorials.

You need to get ahold of the component properly, e.g. by running Destroy(GetComponent(EnemyAI));. But I would suggest you create a static variable, e.g. a bool called canMove, in EnemyAI.js, which controls whether or not the enemy is moving, and then set this variable to false instead of running Destroy().