Anime You Watch and the Descriptions that Love Them

Squid Girl
The invader comes from the bottom of the sea! Squid Girl has come to the land from the depths of the sea to conquer humanity for its pollution of the ocean. Unfortunately she ruins the first house she uses as an invasion base and has to work to pay for repairs. Of course, she can't overcome the Aizawa sisters who manage the house, so who knows whether she can subjugate humankind. This show has been described as Sgt. Frog, but with an cute anthropomorphic squid instead of frogs.

Arakawa Under the Bridge
Kou Ichinomiya is a man who goes through life owing nothing to nobody, but one day his life is saved by a mysterious woman, Nino, a self-proclaimed Venusian who lives beneath a bridge. To pay off this debt she asks that Kou become her boyfriend. Kou's sense of duty keeps him living among the weirdoes and goofballs that populate the area near the Arakawa River, but could he actually be developing feelings towards Nino?

Mawaru Penguindrum
Himari Takakura is terminally ill. One day while at the zoo with her brothers Kanba and Shouma, she collapses and passes away. But all is not lost, since a magical penguin hat of dubious origins revives Himari, who then orders her brothers to seek out an item known only as the "Penguindrum." The siblings, now joined by three penguins (also of dubious origins), meet a girl named Ringo who has a special diary that may turn out to be the item they seek. But can they convince her to help them before the diary is snatched away by those who also want its power?

Katanagatari
Yasuri Shichika is the 7th head of the Kyotou school of sword arts, who lives on a nearly-deserted island with his younger sister, Nanami. One day he's approached by a female samurai and self-styled strategist named Togame who's hoping to convince him to use his skill to retrieve 12 very special swords from the various treacherous ninja who've stolen them. What Shichika doesn't realize is that these ninja aren't the only adversaries he has to face, and that his conflict will become much more personal before its conclusion.