How to do it...

To make a custom cursor appear when the mouse is over a GameObject, follow these steps:

1. Create a new Unity 2D project.
2. Import the provided folder, called Images. Select the unity_logo image in the Project window. Then, in the Inspector window, change Texture Type to Sprite (2D and UI). This is because we'll use this image for a 2D Sprite GameObject and it requires this Texture Type (it won't work with the Default type).

3. Go to 2D Object | Sprite to add the necessary GameObject to the scene. Name this New Sprite, if this wasn't the default name when it was created:
   • In the Inspector window, set the Sprite property of the Sprite Renderer component to the unity_logo image. In the GameObject's Transform component, set the scaling to (3,3,3) and, if necessary, reposition Sprite so that it's centered in the Game window when the scene runs.
   • Go to Physics 2D | Box Collider to create a Box Collider and add it to the Sprite GameObject. This is needed for this GameObject to receive OnMouseEnter and OnMouseExit event messages.
4. Import the provided folder called IconsCursors. Select all three images in the Project window and, in the Inspector window, change Texture Type to Cursor. This will allow us to use these images as mouse cursors without any errors occurring.
5. Create a C# script class called CustomCursorPointer containing the following code and add an instance as a scripted component to the New Sprite GameObject:

using UnityEngine; 

public class CustomCursorPointer : MonoBehaviour { 
  public Texture2D cursorTexture2D; 
  private CursorMode cursorMode = CursorMode.Auto; 
  private Vector2 hotSpot = Vector2.zero; 

  public void OnMouseEnter() { 
    SetCustomCursor(cursorTexture2D); 
  } 

  public void OnMouseExit() { 
    SetCustomCursor(null); 
  } 

  private void SetCustomCursor(Texture2D curText){ 
    Cursor.SetCursor(curText, hotSpot, cursorMode); 
  } 
}

6. With the New Sprite item selected in the Hierarchy window, drag the CursorTarget image into the public Cursor Texture 2D variable slot in the Inspector window for the Custom Cursor Pointer (Script) component:

7. Save and run the current scene. When the mouse pointer moves over the Unity logo sprite, it will change to the custom CursorTarget image that you chose.