yichael_smartbow/Assets/BowArrow/Scripts/Game/ArrowLightSick.cs

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

public class ArrowLightSick : MonoBehaviour
{
    [SerializeField] Material[] defaultMats;
    [SerializeField] Material lightSickMat;

    static HashSet<ArrowLightSick> set = new HashSet<ArrowLightSick>();

    void Start()
    {
        set.Add(this);
    }

    void OnDestroy()
    {
        set.Remove(this);
    }

    public void Hit() {
        MeshRenderer mr = this.GetComponent<MeshRenderer>();
        Material[] mats = mr.materials;
        mats[1] = lightSickMat;
        mr.materials = mats;
    }

    void Recovery() {
        MeshRenderer mr = this.GetComponent<MeshRenderer>();
        mr.materials = defaultMats;
        
    }

    public static void RecoveryAll()
    {
        foreach (var item in set)
        {
            item.Recovery();
        }
    }
}