GP7_GAMEN4_AR_Shooting_Unity/Assets/myFolder/Scripts/EnemyMovement.cs

using UnityEngine;

public class EnemyMovement : MonoBehaviour
{
    private void Start()
    {

    }
    void Update()
    {
        // Float up and down
        float yMove = Mathf.Sin(Time.time * 2f) * 0.005f;
        transform.Translate(0, yMove, 0);

        // Always look at player
        transform.LookAt(Camera.main.transform);
    }
}