Zeron was the third Gori Kaiju that appear in Episodes 3 (Threat of Midoron) and 4 (Rah/Karas, Search among the Earthlings) of the Spectreman TV series.

While the third Monster of the show, Zeron was the first to be portrayed by a man in a suit, as the first two, Hedoron and Midoron, were both puppets and miniatures – with Stop-motion been use in the case of Midoron. It was also the first to force Spectreman to turn into a giant for the first time.

During the events of The Threat of Midoron, Zeron was used by Gori to begin construction of his secret base on Earth, while Rah/Karas sow Chaos with Midoron and the Blue Scum, but after Midoron's death at the hands of Spectreman and Rah's deviancy in taking a Rita, Gori was forced to use Zeron to attack Spectreman to help Rah, less his base was found out, though the Battle with Spectreman did not happened until - and only at the start of - Ep.4.

Zeron emerged from the ground and combat the Cyborg Hero, forcing him to transform into its Giant Form, the first time he did so in the show. The battle, while rough for our hero, it was brief, as Spectreman muster its strength to toss Zeron away and finishing it off with Spectre Flash. The rest of the Episode had Rah studying Human behavior in a largely comedic situations and no other Kaiju was featured.

Appearance wise, Zeron resembled ceratopsian dinosaur, witch a heavily armored like body, with a very noticeable row of spine and long tail; its head was adorn with a crown of 5 Horns, with a single Horn in the snout. Its only power was to burrow its way under the ground and its combat skills were largely physical, though it was stronger than Spectreman, which forced him to use Spectre-flash on it. Its roar were a screech.

The Costume would later be reuse and modify to be Magnosaurus for episodes 40 and 41.