It had stalked eyes, sharp teeth, and a mouth on the end of a long tube.

So what the hell was it?

Scientists have been asking that question since 1958, when amateur collector Francis Tully found the first known fossil of the ancient creature—dubbed Tullimonstrum gregarium, or the “Tully monster,” after him.

Today biologists have finally pinned it down. The Tully monster was a primitive vertebrate, most closely related to today’s lamprey eels and other jawless fish. It lived in what is now Illinois about 307 million years ago, when most of the proto-state was under water. Its stalked eyes and teeth probably mean it was a predator.

So now you know. You're welcome.