It’s a Halloween episode! “There’s a scary secret lurking in the kitty litter…” We’re making a horror movie about a common cat parasite - that can control minds! Toxoplasma gondii makes mice lose their fear of cats, in a plot to take over the world! Biologist Sebastian Lourido helps us tell the true tale of toxoplasma’s quest for cat domination, and what scientists are doing to stop the parasite in its banana-shaped tracks.