MonoBehavior.Start() called infinite times?

So, I'm running a simple instantiate() script to duplicate gameObject, genOrig once on a random point between 4 and -4 on the X-Axis. Simple enough, right? However, when I start the script, Unity creates a clone of the game object every frame, like an Update() message.

Here's my code: using UnityEngine; using System.Collections;

 public class GenerationScript : MonoBehaviour {
 
     public GameObject genOrig;
     public Quaternion rot;
     public float posX = Random.Range(-4f, 4f);
 
 
     // Use this for initialization
     void Start () {
         Vector3 position = new Vector3 (posX, 0, 0);
         Instantiate (genOrig, position, rot);
     }
     
     // Update is called once per frame
     void Update () {
     
     }
 }

I suspect something strange is calling Start() every frame. Help please?