Aoi, a regular boy, is cursed with a spell that turns him into a frog whenever he gets wet. He is sent to another world with a frog kingdom to find the princess to undo the spell. When he finds out that she doesn't know how to lift the curse, they set out to find the spell that will. Along the way they meet many interesting creatures, come across many dangers, and make many new friends. (Source: ANN)

Pet shop owner's daughter Chika Tokorozawa spends every waking hour with her dog, Rin Tin Tin, who repays her love by watching over her while she sleeps. Based on the manga in Young Sunday magazine by Maki Otsubo, who is better known in the manga world for Mr. Cinema. (Source: Anime Vice)

During a vacation Natsumi is visited by a female alien and male alien who she later gains feelings for from the ocean that makes her the Deep Sea Princess who, along with the rest of the Keroro Platoon, encounter many dangers summoned by a mysterious creature. (Source: Wikipedia)

It is the year 2004 AD, and pandemonium breaks as a mysterious frog-like alien race fills the sky with UFOs—or so 12-year-old Fuyuki Hinata dreams. Coincidentally, Sergeant Keroro, leader of a preliminary squad for the Keronian invasion of Pekopon—the alien name for Earth—begins his mission by invading Fuyuki's home. After subduing the boy and his sister, Keroro plans to reunite with his comrades and return to the mothership to repair his invaluable invasion device, the Kero Ball. Unfortunately, he receives word that headquarters has abandoned his unit's retrieval due to an unprecedented issue that forced the rest of the Keronians to flee. Consequently, Keroro is forced to stay at the Hinata residence together with the friendly, starry-eyed Fuyuki; his athletic, short-tempered sister Natsumi; and their hardworking, attractive mother Aki. Now stuck until further notice, Keroro and his platoon spend each day plotting world domination, but are thwarted each and every time by various unexpected factors. Nevertheless, as they live alongside humans, they learn to treat them as friends and allies, forming comedic yet meaningful connections that make their lives on Earth worthwhile.