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

public class MoveObject : MonoBehaviour
{
    public float speed;

    void Update()
    {
        transform.Translate(new Vector2(-1, 0) * Time.deltaTime * speed);
    }
}

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

public class DestroyObject : MonoBehaviour
{
    private void OnCollisionEnter2D(Collision2D collision)
    {
        // 何かにぶつかったら、自分を破壊する
        Destroy(this.gameObject);
    }
}

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

public class SelfDestroy : MonoBehaviour
{
    // このメソッドは外部から呼び出すので、必ず「public」にすること（重要）
    public void DestroyExplosion()
    {
        Destroy(this.gameObject);
    }
}

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

public class DestroyObject : MonoBehaviour
{
    // ★追加（エフェクト）
    public GameObject effectPrefab;

    private void OnCollisionEnter2D(Collision2D collision)
    {
        Destroy(this.gameObject);

        // ★追加（エフェクト）
        Instantiate(effectPrefab, transform.position, Quaternion.identity);
    }
}