change toggle sprite on click unity code example

Example 1: Changing scene on obj click

void OnMouseDown ()
      {
          SceneManager.LoadScene("Level2");
      }
// make sure to use your level name

Example 2: how to make a button disapear on click in javafx

public void letterChosen(ActionEvent event) {
    Button source = (Button) event.getSource();
    source.setVisible(false);
    System.out.println("pick: "+source.getUserData());
}