<h3>¡Atrápame, si puedes!</h3>
<section id="contenedor">
  <div id="fantasma">
  </div>
</section>  
h3 {
  text-align: center;
}

#contenedor {
  position: relative;
  width: 560px;
  height: 300px;
  margin: 0 auto;
  background-color: #333;
}

#fantasma {
  position: absolute;
  left: 250px;
  top: 100px;
  width: 50px;
  height: 60px;
  background-color: white;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.0/jquery.min.js