A team of time-travelling Daleks appears, pursuing the Doctor and his friends, and the Mechonoids defend their city in a ferocious battle.

He originally called the creatures Mechons (pronounced Meck-ons), and the first draft of his script described them: "It is a mechanical robot that moves on the same principle as the Daleks... legless.

[1]In Episode 6, "The Planet of Decision", Nation envisioned the Mechons keeping the travellers in a human zoo, along with a stranded astronaut who arrived five years earlier and was captured by the robots.

She suggested that instead of the Mechons establishing a human zoo, "they could be programmed to imprison any new arrivals who lack knowledge of the decoding system used by the expected colonists.

The misspelled "Mechanoid" was also used extensively in merchandising and in print, including the 1965-66 TV Century 21 comics and the 1965 annual The Dalek World.

According to Doctor Who: The Complete History, "For one shot, of a Mechonoid destroyed by a Dalek, a special pre-cut upper dome was rigged to collapse on cue, with smoke emitted from dummy mechanics inside the casting.

"[1] The operators hired by director Richard Martin had previously worked with him on serials featuring the Daleks or the Zarbi (from the 1965 story The Web Planet).

[6] The Mechonoids' climactic battle with the Daleks was shot on film at Ealing Studios, on stage 3A/B on Wednesday 14 and Thursday 15 April, 1965.

The battle scene, cut in on telecine, now incorporated cross faded images, and several animated explosions superimposed on the action.

[12] Problems experienced during the recordings with moving the bulky props brought a swift end to the production's plans for a return match between the Daleks and Mechonoids.

[18] Cherilea Toys, who had success with their Swappit Dalek kits, also tried to capitalize on the Mechonoids, producing two-inch plastic models in black, light blue and silver, which could be broken into detachable pieces and put back together in different colour combinations.

The publication featured a weekly one-page series, The Daleks, which depicted the metal monsters in full color as galactic conquerors.

[5] A contemporary review in The Stage and Television Today praised the final episode of The Chase, with Marjorie Norris writing, "The battle scene between the two opposing robot armies — the Daleks and the Mechanoids (sic) — was handled with imagination and ingenuity to provide a spectacle as exciting as many that have been achieved at far greater cost in feature films.

"[15] Tat Wood and Lawrence Miles took a dimmer view of the Mechonoids in their book About Time, volume 1, writing, "And that's humanity's idea of a servo-robot, is it?

An impractically large and clumsy ball of metal that shuffles along very, very slowly and has no obvious functions except for building corridors that are flagrantly too small for it.

"[20] Elizabeth Sandifer agreed in Tardis Eruditorum, volume 1: "The thing is, in the sixth episode, it's quickly clear that the Mechanoids are rubbish and everyone knows it.

"[22] War of the Daleks (1997), an Eighth Doctor BBC Books novel written by John Peel, features a Mechonoid identified as Mechon 179.

The Mechonoids appear in the 2005 Big Finish Productions audio drama The Juggernauts by Scott Alan Woodard, which features the Sixth Doctor and Melanie Bush.

In this story, Davros adds human nervous tissue to robotic Mechanoid shells to create the titular Juggernauts.