<p><i>Antheraea polyphemus</i> caterpillar.
</p>
I snapped this shot as the caterpillar "walked" off the tip of a branch, from the underside.  Taken using a Canon EF 100mm f/2.8 Macro USM.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/58431807@N06">photochem_PA</a>
CC BY 2.0
<a href="//commons.wikimedia.org/wiki/Flickr" class="mw-redirect" title="Flickr">Flickr</a>: <a rel="nofollow" class="external text" href="https://www.flickr.com/photos/58431807@N06/6154649460">Portrait of a green caterpillar (Antheraea polyphemus)</a>