Sarotrocercus was a pelagic animal, meaning that it is in mid-water, and in the Burgess Shale, mid-water animals survived the mudslide, which mainly buried nektobenthic and benthic animals.
This image shows a close-up of Sarotrocercus, because Sarotrocercus only grew up to two centimeters. But that's definitely not the smallest animal in the Burgess Shale because Haikouichthys was probably one of the smallest, because it was only one centimeter. That's the size of your thumbnail. Sartotrocercus had two big compound eyes on stalks, two feeding appendages right next to the eyes, many gills on the bottom (which was usually the top), and weirdest of all, Sarotrocercus had a long tail with a club of spines at the end, which was probably used for defense.
I have a video of myself doing today's post.