Keroro Platoon, Real Dragon Warriors / Mois, That One Other Person's Spring
To save Planet Keron from a super-powerful cosmic enemy, the frogs of the Keron Platoon metamorphose into dragons! Then, Mois helps her doppelgänger Asami to study for her last university entrance exam! Source: crunchyroll
Aired 26/03/2011EP 356 - Keroro Platoon, Real Dragon Warriors / Mois, That One Other Person's Spring
Sgt. Frog
Keroro is a frog-like alien sent from his home planet on a mission to conquer Earth. But when his cover is blown, his battalion abandons him and he ends up in the home of the Hinata family. There, he's forced to do household chores and sleep in a dark basement that was once supposedly a prison cell haunted by the ghost of an innocent girl. He even spends his free time assembling Gundam model kits. During his stay, Keroro meets up with subordinates who were also stranded during their failed invasion.
(Source: Anime News Network)