Sixty-six million years ago, a marine creature, minding its own business at the bottom of a Cretaceous sea, munched on some sea lilies—then didn’t feel too great. Now, a fossil hunter in Denmark named Peter Bennicke has found the remains of this Cretaceous snack: fossilized vomit.

A cluster of 66-million-year-old fish vomit is a natural, national treasure in Denmark. The rare find shines a light on the sea animals of the Cretaceous period.

In the Cretaceous period, a shark or another kind of fish found sea lilies less than digestible. What you might expect followed.