Zoids (ゾイド), short for Zoic Androids, is a franchise based around a series of plastic toy models designed and produced by Japanese toy company Tomy (now Takara-Tomy). First released in 1982, the models resemble a range of creatures including mammals, dinosaurs, and insects. The majority are in 1:72 scale with a wind-up or battery-powered motor to power moveable features, and feature snap-together construction and precolored parts.

The original line of toys was released in Japan, Europe, and the United States in the 1980s. While the American line was storyless, Zoids in Japan soon had a "Battle Story" told in text on the back of the model boxes, in "fanbooks", and in catalogues. It described the Zoids as metal-based lifeforms rebuilt into mecha and used in a series of wars on Planet Zi and the lives of the native Zoidians involved. Zoids fans in the UK were treated to their own storyline, featured in the comic Spider-Man and Zoids, which differed considerably, dividing the Zoids into warring Red and Blue factions with a party of humans caught in between.

The Zoids franchise also includes five anime series (the first starting in 1999), numerous manga series, and many electronic games, most of which inhabit their own unique continuities independent of the others. Two of the more recent toy lines have been tie-ins to the anime series.

Source: Wikipedia