The fourth episode of Russell T. Davies’ children’s science fiction series Wizards vs. Aliens airs on CBBC., starring Annette Badland, Brian Blessed (Flash Gordon), and Gwendoline Christie (Game Of Thrones). 
Trapped in Benny’s house with the Grazlax, Tom discovers only too late that trying to ward the alien creature off with a hair dryer simply allows it to reproduce. Once the creature finds the ecologically friendly boiler Benny’s dad has built in the basement, it starts to reproduce almost at will, each “generation” creating three new Grazlax from the remains of a single Grazlax. The boy discover that high-pitched sound has an effect on their pursuers, and in space, the Nekross discovers that the Grazlax may be too powerful for even their technology to control.
written by Phil Ford
directed by Daniel O’Hara
music by Sam Watts
Cast: Scott Haran (Tom Clarke), Percelle Ascott (Benny Sherwood), Annette Badland (Ursula Crowe), Jefferson Hall (Varg), Gwendoline Christie (Lexi), Brian Blessed (voice of the Nekross King), Tim Rose (Nekross King puppeteer), Dan Starkey (Randal Moon), Manpreet Bambra (Katie Lord), Dave Chapman (Grazlax), Robert Tygner (Grazlax)
LogBook entry by Earl Green