オブジェクトをインスペクターにアタッチしましたがアサインされません

エラーの内容は
「UnassignedReferenceException: The variable TrapSpike1 of Traps has not been assigned.
You probably need to assign the TrapSpike1 variable of the Traps script in the inspector.
UnityEngine.GameObject.GetComponent[T] () (at <2fae0a4cbcec42c9acc616494aa88f69>:0)
Traps.Start () (at Assets/Scripts/Traps.cs:16)」

です。

TrapSpike1変数がTrapsのインスペクターにアサインされていないということだと思うのですが、インスペクター上ではドラッグ・アンド・ドロップはしています。
ここから更にどうすればよいのでしょうか。

Trapsのコードは以下です。

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

public class Traps : MonoBehaviour
{
    public GameObject TrapSpike1;
    public float trap1jumpPower = 500;

    Rigidbody2D rigidTrap1;
       


    void Start()
    {
        rigidTrap1 = TrapSpike1.GetComponent<Rigidbody2D>();
    }

    // Update is called once per frame
 

    public void Trap1Activate()
    {
        rigidTrap1.AddForce(Vector2.up * trap1jumpPower);
        Debug.Log(rigidTrap1);//NULLになります
    }
}

コード

Trapsを呼び出すコードは以下です。


using UnityEngine;

public class PlayerManager : MonoBehaviour
{

    //public
  
    public float xspeed;
    public float jumpPower;
    public GroundCheck ground;
    public GameManager gameManager;
    //SE
    [SerializeField] AudioClip jumpSE;


    //private
    Traps trap1;
    private bool isGround = false;
    float speed;
    bool isDead = false;
    AudioSource audioSource;

   



    public enum DIRECTION_TYPE
    {
        STOP,
        RIGHT,
        LEFT
    }

    DIRECTION_TYPE direction = DIRECTION_TYPE.STOP;

    Rigidbody2D rigidbody2D;
    Rigidbody2D trapSpike1;
    Animator animator;


    private void Start()
    {
        rigidbody2D = GetComponent<Rigidbody2D>();
        trapSpike1 = GetComponent<Rigidbody2D>();
        animator = GetComponent<Animator>();
        audioSource = GetComponent<AudioSource>();
    }

    void Update()
    {
        if (isDead)
        {
            return;
        }
        //接地判定を得る
        isGround = ground.IsGround();

        float x = Input.GetAxis("Horizontal");

        //speedというパラメータにxを代入
        animator.SetFloat("speed", Mathf.Abs(x));

        if (x == 0)
        {
            //止まっている
            direction = DIRECTION_TYPE.STOP;
        }
        else if (x > 0)
        {
            //右に動く
            direction = DIRECTION_TYPE.RIGHT;
        }
        else if (x < 0)
        {
            //左に動く
            direction = DIRECTION_TYPE.LEFT;
        }

        //スペース押したらジャンプ

        if (isGround)
        {
            if (Input.GetKeyDown("space"))
            {
                Jump();
            }
            else
            {
                animator.SetBool("isJumping", false);
            }

        }

        
        switch (direction)
        {
            case DIRECTION_TYPE.STOP:
                speed = 0;
                break;

            case DIRECTION_TYPE.RIGHT:
                speed = xspeed;
                transform.localScale = new Vector3(1, 1, 1);
                break;

            case DIRECTION_TYPE.LEFT:
                speed = -xspeed;
                transform.localScale = new Vector3(-1, 1, 1);
                break;
        }
        rigidbody2D.velocity = new Vector2(speed, rigidbody2D.velocity.y);
    }
   

    void Jump()
    {
        //上に力を加える
        rigidbody2D.AddForce(Vector2.up * jumpPower);
        animator.SetBool("isJumping", true);
        audioSource.PlayOneShot(jumpSE);

    }

    private void OnTriggerEnter2D(Collider2D collision)
    {
        if (isDead)
        {
            return;
        }
        if (collision.gameObject.tag == "Trap")
        {
            Debug.Log("GameOver");
            gameManager.GameOver();
            PlayerDeath();
        }
        if (collision.gameObject.tag == "Finish")
        {
            Debug.Log("GameClear");
            gameManager.GameClear();
        }

        //トラップSwitchのタグ
        if (collision.gameObject.tag == "Switch1")
        {
            Debug.Log("罠１起動");
            Debug.Log(trap1);
            trap1.Trap1Activate();
          

        }

    }
    void PlayerDeath()
    {
        BoxCollider2D boxCollider2D = GetComponent<BoxCollider2D>();
        Destroy (boxCollider2D);
        rigidbody2D.velocity = new Vector2(0,0);
        rigidbody2D.AddForce(Vector2.up * 400);
        animator.Play("PlayerDeathAnimation");
        gameManager.GameOver();
        isDead = true;
      
    }

}


コード