A Keromet is a mysterious headgear landed on Pekopon from outer space. It was seen buried in the ground and where Shirara (as Shurara) commonly wears for vengeance against Keroro Platoon's leader, Keroro for the tragic past he had done during Shurara's childhood and for Pururu's love.
According to Kururu, the Keromet's true form is a strange extrarrestrial robot that eats planets.
Keromet's first form is a normal inanimate object, in its true form, it was very enormous and a ferocious monster, and its also slightly aggressive.
The axe-like horns on each sides acts like boomerangs, and mechanical tentacles from the Keromet's back to whip its enemies away.
The Keromet appears to have some superficial similarities to Unicron from Transformers. Both are planet eating beings and also have similar appearance i.e. horns, tentacles, color scheme.