What plant-based toxin makes predators go savage in Zootopia?

The plant-based toxin that makes predators go savage in Zootopia is called Night Howler. Although the name initially sounds like it refers to a dangerous animal, Night Howlers are actually flowers with powerful psychotropic effects when ingested or processed.

Judy Hopps first hears the term from the jaguar Manchas after he suddenly becomes feral. Later, she realizes the flowers are the “night howlers” her parents grow as a crop-control problem in Bunnyburrow. That discovery changes the investigation: the predators are not reverting because of their biology, but because someone is deliberately exposing them to the flower’s extract.

Ram chemist Doug turns Night Howler bulbs into a serum and fires it into predators with a dart gun. Dawn Bellwether uses the resulting panic to promote fear of predators and strengthen her political position. The mystery therefore combines a botanical clue with a conspiracy plot. “Savage root” and the other alternatives are invented names, not terms used in the film.