Terror of the Terra-Firmians is a cartoon written by Francisco Angones and a team of writers (see Infobox) and directed by Tom Owens and Matthew Humphreys. It features Huey, Dewey and Louie Duck, Webby Vanderquack, Lena and Magica De Spell, Launchpad McQuack, Mrs Beakley, and, in their debut, the Terra-Firmians.
Webby, Huey, Dewey and Louie are led by Lena De Spell to an abandoned railway track beneath Duckburg where there have been frequent sightings of mysterious creatures known as Terra-Firmians. Webby has daydreamed about their existence her whole life long and is extremely excited to meet them, but Huey, on the other hand, refuses to acknowledge their existence because they're not in the Junior Woodchucks Guidebook. Meanwhile, Mrs Beakley and Launchpad follow the children to try and get them back to safety.
Behind the scenes
Terror of the Terra-Firmians is the fifth episode of the DuckTales 2017 series.
Eric Geron novelized it as DuckTales: Tunnel of Terror! in July 2018.