It’s frustrating and gross, but we’ve all done it. We’ve all stepped in poop.

Most of us would like to forget the experience. But 33 million years ago, now-extinct life forms stepped in it, and fossilization has ensured that those events will not be forgotten.

For archeologists, what was once repellent is now an absolute marvel, as it offers insight into extinct animals and their environments that we may not otherwise obtain. Similarly, other byproducts of life we might find disgusting—regurgitated remnants of meals, internal organs and their contents—are important clues into creatures we only know about from the fossil record.