Takurou Mukoujima is your ordinary High School boy who likes to go fishing at the pier in the afternoon. One day, he accidentally caught a green-haired mermaid named Muromi and an unlikely friendship between the two began.Namiuchigiwa no Muromi-san (Muromi of the Shore) is a gag manga by Najima Keiji serialized on Shonen Magazine Comics. It received a thirteen-episodes anime adaptation which starts airingaired from April 6th of 2013 with twelve minutes length per episode. Now available for viewing at Crunchyroll.
Double Entendre: All the mermaids' act and descriptions of joy of eating cucumber can easily be interpreted naughtily.
The Dreaded: Muromi is basically Satan to the entire Coelacanth species, due to her scaring the tar out of one who was on the verge of evolving into a land animal back in prehistoric times. The fear actually gets genetically encoded in their DNA and is passed down to the future generations.
Erotic Eating: With cucumbers. Also, note how Sumida and Hii-chan hold theirs at the end of episode 7.
Evolving Credits: A small, subtle example in the opening. After episode 9, Yeti now sports the fluffy tail Wiseman gave her.
E.T. Gave Us Wi-Fi: Discussed in episode 9. Turns out, all the weird gadgets Muromi has (Including her camera phone) were given to her a long time ago by the alien Wiseman. It also turns out he's responsible for giving advanced technology to the people of Mu, which lead to their destruction (and its why he is no longer allowed to give his technology to humans).
The Friend Nobody Likes: According to Muromi in episode 10, nobody likes the Kraken. Due to him being an obnoxious lightweight, who almost caused World War 3 to impress people. They agree to get him wasted and stick him with the bill at a mixer.
From the Mouths of Babes: Harpy starts spouting random internet slang and insults in Episode 9. Wiseman taught her those words.
Gainaxing: Fuji-san's twin mountains jiggling this way and that was practically the plot point for the penultimate episode.
Gag Boobs: Fuji-San, and as a result the fifth episode preview mainly consists of her breasts bouncing.
Kappa: Kawabata-san, yet another friend of Muromi. Unlike stereotypical kappa who is short and timid, he's huge, muscular, and is a manly man of few words. He doesn't like humans, but he considers Takkun a friend since Takkun is Muromi's friend.
Reality Retcon: The Mongol invasion of Japan (approximately 800 years ago) was stopped by mermaids' singing which caused a big storm. Later on, Witch Trials were abolished because of Levia-san's rampage to avenge Muromi.
Riches to Rags: Otohime, because the Sea Dragon Castle went out of business.
Spoiler Opening: It's not like plot matters considering the show's premise, but several characters make an appearance in the opening way before their debut in the series (most notably Ciel and Wiseman).
Time Abyss: Muromi and the other mermaids have been around since the Mesozoic Era, if not longer. Played for Laughs; she constantly hints at being ridiculously old so she can punt Takkun when he "rudely" asks how old she is.