Rex the Runt is a series of 10-minute short sitcom episodes, about the television adventures of four dogs. Rex, the self-styled leader of the gang, is considered a bit of smart-arse amongst the friends. His pals are Wendy, an intelligent yet grumpy canine whose ideas are often stolen by the others; obese gun-and-shed-lover Bad Bob, described by Wendy as a big, fat, jelly, wobbly, fat bastard; and the monosyllabic Vince, known for his love of Tuesday and his 'Random Pavarotti Disease' outbursts.

The series features a mixture of surreal plots, which involve the dogs traveling through time, space, to the North Pole - and even Birmingham. The adventures include Rex being put through a mincer, being kidnapped by an alien plant pot looking for people called 'Gordon', digging a hole to Australia in the back garden, and a journey inside Vince's brain.

The series features many recognisable voices from the world of British comedy and culture. Guests include Paul Merton, Arthur Smith, Graham Norton, Phill Jupitus, Pam Ayres, Tommy Cannon, Bobby Ball, Eddie Izzard, Bob Monkhouse, Bob Holness, June Whitfield, Judith Chalmers, Lloyd Grossman, and Stanley Unwin, in his final television role.

The series was created, directed and co-written by Richard Goleszowski, who has also worked on Robbie the Reindeer, Creature Comforts, children's TV programme Morph and Peter Gabriel's famous 1986 Sledgehammer music video