Various forms the Eater can assume.
The Eaters are the main villains from the unreleased Arcade game Chimera Beast. They are a mutant species that naturally emerged on a planet similar to Earth. These monstrosities only purpose is to consume other lifeforms, assimilating their DNA to continually evolve, acquiring the characteristics of their prey.
The player controls one such Eater, starting as a microorganism preying on bacteria and other microbes. Each stage has the Eater climbing one step further on the food chain, taking on fish, birds, reptiles and mammals. By the penultimate stage, the Eater attacks mankind, being giant enough to destroy whole buildings. At the end of the stage, it destroys a nuclear power plant, thus causing a nuclear holocaust. The final stage has the Eater preying on other Eaters while the nuclear explosion destroys the planet.
After destroying a human space shuttle attempting to flee the planet and another giant-sized Eater, all life on the planet is extinguished, so the Eater continues traveling the universe, searching for more victims and destroying more planets, until one day when it will finally reach Earth.