Object Reference Not Set to an Instance of an Object?

So I have two points, I need to instantiate an object between them when a trigger is entered. Here are my two scripts.

 using UnityEngine;
 using System.Collections;
 
 public class BallMove : MonoBehaviour
 {
     public float speed = 1f;
 
     private int dir;
     private Intersections inters;
     private CreateObstacle createObstacle;
 
     void Start()
     {
         createObstacle = GetComponent<CreateObstacle>();
     }
 
     void OnTriggerEnter(Collider c)
     {
         if(c.tag == "Intersection")
         {
             inters = c.GetComponent<Intersections>();
             dir = Random.Range(0, inters.intersections.Length);
 
             createObstacle.InstantiateObstacle(current: inters.transform, next: inters.intersections[dir].transform);
         }
     }
 
     void Update()
     {
         if(this.transform.position != inters.intersections[dir].position)
         {
             this.transform.position = Vector3.MoveTowards(this.transform.position, inters.intersections[dir].position, speed * Time.deltaTime);
         }
     }
 }
 

And the one with the function to create the object.

 using UnityEngine;
 using System.Collections;
 
 public class CreateObstacle : MonoBehaviour 
 {
     public GameObject obstacle;
 
     private Vector3 middlePoint;
 
     public void InstantiateObstacle(Transform current, Transform next)
     {
         middlePoint = Vector3.Lerp(current.position, next.position, 0.5f);
         Instantiate(obstacle, middlePoint, Quaternion.identity);
     }
 }

I really don't know what I'm doing wrong.