How to show fields of referenced entity when referencing entity is being loaded?
Depending on where you want to create the block/ show the information the way to retrieve the data from the referencing node may vary. Here's a simple example for rendering from within a node.tpl.php:

$referenced_node=node_load($node-&gt;reference_field['und'][0]['target_id']); 
print drupal_render(field_view_field('node', $referenced_node, 'field_something', 'displayname'));


This solution makes use of standard Drupal rendering methods/ display suite rendering for your referenced node. Change displayname to the proper display you want to use for rendering, you might want to add a custom one with different settings.