The source code behind my Unity tip.

AnimatedComponent.cs

using UnityEngine;
using System.Collections;

// This is not need but I just wanted to make the point clear. 
public class AnimatedComponent : MonoBehaviour
{
}

AnimatedEditor.cs

using UnityEngine;
using UnityEditor;
using UnityEditor.AnimatedValues;

[CustomEditor(typeof(AnimatedComponent))]
public class AnimatedEditor : Editor
{
    private class Styles
    {
        public readonly GUIStyle lennyFaceStyle;
        public readonly GUIStyle lennyTextStyle;
        public readonly GUIStyle messageStyle;

        public Styles()
        {
            lennyFaceStyle = new GUIStyle(EditorStyles.boldLabel);
            lennyFaceStyle.fontSize = 40;
            lennyFaceStyle.stretchWidth = false;
            messageStyle = new GUIStyle(EditorStyles.boldLabel);
            messageStyle.alignment = TextAnchor.MiddleLeft;
            messageStyle.fontSize = 14;
        }
    }

    private AnimBool m_FoldoutOpen;
    private GUIContent m_LennyFace;
    private GUIContent m_LennyText;
    private Styles m_Styles;

    public void OnEnable()
    {
        m_FoldoutOpen = new AnimBool();
        m_FoldoutOpen.target = false; // Default to not open
        m_FoldoutOpen.valueChanged.AddListener(Repaint);
        m_LennyFace = new GUIContent("( ͡° ͜ʖ ͡°)");
        m_LennyText = new GUIContent("oh hai");
    }

    public void OnDisable()
    {
        m_FoldoutOpen.valueChanged.RemoveListener(Repaint);
    }

    public override void OnInspectorGUI()
    {
        if (m_Styles == null)
        {
            m_Styles = new Styles();
        }

        // Target is where it's going to
        m_FoldoutOpen.target = EditorGUILayout.Toggle("Open", m_FoldoutOpen.target);
        // Do our fade group
        if (EditorGUILayout.BeginFadeGroup(m_FoldoutOpen.faded))
        {
            GUILayout.BeginHorizontal(GUI.skin.box);
            {
                GUILayout.Label(m_LennyFace, m_Styles.lennyFaceStyle);
                GUILayout.Label(m_LennyText, m_Styles.messageStyle);
            }
            GUILayout.EndHorizontal();
        }
        EditorGUILayout.EndFadeGroup();
    }

}