station_obscurum_unity/Assets/Scripts/DGemItem.cs

using UnityEngine;

public class DGemItem : MonoBehaviour
{
    [SerializeField] private float decSpeed = 5f;

    // Start is called before the first frame update
    private void Start()
    {
    }

    // Update is called once per frame
    private void Update()
    {
    }


    private void OnTriggerEnter(Collider collision)
    {
        if (collision.gameObject.CompareTag("Player"))
        {
            collision.gameObject.GetComponent<PlayerMovementController>().SetSpeed(decSpeed);
            Destroy(gameObject);
        }
    }
}