If you come across one of these goopy colonies, don't fear! While they may be gross, they are native to the Great Lakes and harmless to the waters.

The fossil was found at a cliff in Denmark. Fossilized vomit is called regurgitalite, and it's a type of trace fossil, which tells scientists about an organism's daily life.

The fossil also appears to contain bryozoans, Olsen says, very tiny creatures that are also called moss animals, but it's unclear if they were part of the fish's attempted meal in this case.