<!-- BEGIN COPY / PASTE -->
    // JavaScript: Register the block
    wp.blocks.registerBlockType('myplugin/dynamic-block', {
      title: 'Dynamic Block',
      category: 'widgets',
      edit: function() {
        return wp.element.createElement('p', null, 'Dynamic Content Block');
      },
      save: function() {
        return null; // Rendered in PHP
      }
    });

    // PHP: Render the block content
    function myplugin_dynamic_block_render_callback() {
      $dynamic_content = get_some_dynamic_data(); // Fetch dynamic data
      return '<div>' . esc_html($dynamic_content) . '</div>';
    }
    register_block_type('myplugin/dynamic-block', array(
      'render_callback' => 'myplugin_dynamic_block_render_callback',
    ));
    <!-- END COPY / PASTE -->