FloatySpinny.cs

using UnityEngine;

public class FloatySpinny : MonoBehaviour
{
    public bool m_Spin = true;
    public Vector3 m_SpinAxis = Vector3.up;
    public float m_SpinSpeed = 1.0f;

    public bool m_Float = false;
    public Vector3 m_FloatAxis = Vector3.up;
    public float m_FloatSpeed = 0.25f;
    public float m_FloatDistance = 0.1f;

    private Vector3 m_OriginalPos;
    
    void Start()
    {
        // cache the original position
        m_OriginalPos = transform.transform.localPosition;
    }
    void Update()
    {
        if (m_Spin)
        {
            // advance the rotation
            transform.rotation = transform.rotation * Quaternion.Euler(m_SpinAxis * (Time.deltaTime * m_SpinSpeed));
        }

        if (m_Float)
        {
            // advance the "floaty"
            transform.localPosition = m_OriginalPos + (m_FloatAxis * (m_FloatDistance * (Mathf.Sin(Time.time * m_FloatSpeed))));
        }
    }
}