Most caterpillars are easily handled. No problem. However, there are some that do not like to be touched. For instance, the caterpillar in this photo uses his urticating setae to funnel poison from a special glandular cell to anything that touches him. The spines stick in your skin if you touch it and then break away from the caterpillar's body and spill the toxins on your skin. Things can get pretty nasty in a hurry. This particular caterpillar, Streetus Lightus, also sports a single luminescent eyeball that he uses to illuminate people who touch him to capture that instant when the subject realizes he shouldn't have touched. The caterpillar posts these snapshots on Pillr. Some of the facial expressions he captures are priceless.
(that's not really a caterpillar in the photo, folks)
Ocean Beach, California 2013