collision wont work when i use a prefab

Questions & Answers
1

code on the bullet:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Bullet : MonoBehaviour
{
public int secondsBeforeDestroy;

public void OnCollisionEnter2D(Collision2D collision)
{
    if (collision.gameObject.tag == "Enemy")
    {
        Destroy(collision.gameObject);
        Debug.Log("Collision");
    }
}

void Start()
{
    StartCoroutine(DestroyBullet());
}

IEnumerator DestroyBullet()
{

    //yield on a new YieldInstruction that waits for secondsBeforeDestroy seconds.
    yield return new WaitForSeconds(secondsBeforeDestroy);

    //After we have waited secondsBeforeDestroy seconds Destroy This GameObject print the time again.
    Destroy(gameObject);
    Debug.LogWarning("Destroyed Bullet");
}

}

2

never mind my enemy was set to is Trigger Haha funny fix!