Here is the code in which I was talking about. I can't figure out why my collider isn't working:

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

public class SphereCollider : MonoBehaviour
{
    GameObject obj;
    void Awake ()
    {
        obj = GameObject.FindGameObjectWithTag("Player");
    }

    // Update is called once per frame
    void Update()
    {
        void OnCollisionEnter(Collision collision)
        {
            if (collision.gameObject.name == "Player")
            {
              obj.GetComponent<Health>().health -= 25;
            }
        }

        }
}

```