Regina G. Barber

I think of cordyceps, the parasitic fungus that inspired the video game-turned-TV series The Last of Us, the one that in real life bursts out of the head of ants and controls them when they're dead.

Or I think of people finding a tapeworm in their bodies after eating raw meat.

Those have haunted me since childhood.

And even more unsettling, I was reminded recently by a paleontologist that parasites have been around a lot longer than I had thought.

Carmen Nenglu's that paleontologist.

He's at the University of California, Riverside, and he says trying to trace how far back parasites popped up is hard work.

They're rare to find in fossils.

Among other things, they tend to be made of only soft tissue that doesn't preserve well in rock.

Sometimes researchers get clues that only give a small portion of the whole mystery.

And like the world's greatest detective, Batman, karma had to deal with a mysterious character.

But in this case, it was a fossil that nobody could figure out.

They did have a name for it, though.

The Riddler.

Like the Batman villain.

Karma's detective skills even helped a mystery outside of his specialty.

A few years ago, while at the University of Toronto, he stumbled upon some fossils that he suspected could be a rare first.

At first, his colleagues didn't think he was onto something.

Then after looking deeper into specimens from the same dig site, they realized...

That's Danielle DeKarl, a paleontologist at the University of Toronto.

Together with her and Karma on today's show, we get into an ancient haunt, parasites.