'Wonderfully-shaped feces' found inside ancient fish skull. What left the pretty poops?

About 9 million years ago, marine worms burrowed into a dead fish's head and left behind a skull full of fossilized poop.

'Wonderfully-shaped feces' found inside ancient fish skull. What left the pretty poops?
About 9 million years ago, marine worms burrowed into a dead fish's head and left behind a skull full of fossilized poop.