Kamen Rider W
Episode 295-A of "Sgt. Frog" titled features the members of the Keroro Platoon finding an artifact that allows two of them to combine into a single Keroro, each with new powers. The episode title is based on "Kamen Rider W"s catchphrase and the resultant transformation resembles that of Kamen Rider W (the characters appear to be split down the middle, with one side being, for example, Keroro and the other Tamama).