In Mari Land, a picturesque world entirely populated by Ridiculously Cute Critters, two miscreants named Kuromi and Baku are imprisoned in a dungeon. One day, they obtain the Melody Key, a magical instrument with dark powers, and escape from the prison. They head to the human world in order to collect Black Notes by making people's dreams come true in horrible ways, with the eventual goal of resurrecting the Spirit of Dark Power. Meanwhile, an acquaintance of Kuromi named My Melody is suspected of helping the two fugitives escape. She is ordered to go to the human world to arrest them and save people's dreams. My Melody arrives in Yumemigaoka City and helps a junior high school student named Uta Yumeno when she falls victim to Kuromi's Melody Key. The two become friends, and My Melody starts living with Uta. After that, My Melody and Uta are involved in various troubles caused by Kuromi, but they solve them using My Melody's Melody Takt, a magical conductor's baton.As each season of the series progresses, newer tasks fall to My Melody and her friends. In ~Kuru Kuru Shuffle!~, My Melody must collect Pink Notes while Kuromi must collect the Black Notes so they can fulfill their wishes. In Sukkiri♪, both My Melody and Kuromi are candidates to become the new Princess of Mary Land. Kirara★ however is a prequel story, taking place before the events of the three anime series. This series revolves around Kirara collecting the missing pieces of the Wishing Star so that she can return to the human world.The irreverent, genre-deconstructing humor saves the show from tasting like diabetes. Much, much Better Than It Sounds.
And Now For Something Completely Different — Sukkuri in general, which distills the formula of the previous series so that every episode is half-length. While the formula is similar, there are many inherent differences, such as how Kuromi doesn't actually use nightmare magic on other people this time.
Breast Expansion — One episode features a girl who uses magic to make her chest bigger by "stealing" size from other girls, including their incredibly buxom tennis teacher. But it backfires spectacularly on her when she gets, shall we say, greedy. Hilarity Ensues.
Cute Witch — My Melody, with emphasis on the cute.
Dangerously Genre Savvy — When Hedgehog-kun, who is shown to be the one that restores normalcy after My Melo's battles, tries to roll back after Hiiragi starts playing the Song of the Dark Power, DAR-chan zaps him. He doesn't recover until after the world's been saved.
DAR-chan gets even more savvy the second time around.
Demonic Possession — The Big Bad, Spirit of the Dark, has no physical form, and must possess other beings to further its goal.
Disproportionate Retribution — Arguably the root cause of the entire series. My Melo has apparently been accidently emberasing Kuromi for years, and messing up her life. She has done this literally thousands of times, and most of them are the result of My Melo trying to HELP Kuromi.
The Ditz — My Melody, and some inhabitants of Mari Land, in particular the elephant King.
Forgotten Birthday — in a show full of teenage girls (and girlish bunnies), you pretty much expect this.
Gosh Hornet: In the first episode of Kirara, Kuromi tells a story about an unfortunate picnic mishap that eventually led to her disturbing a beehive and getting stung.
Gotta Catch 'Em All — Both My Melo and Kuromi are trying to collect a specific number of Pink and Black Notes respectively.
Groin Attack — In Episode 2, the Monster of the Week is defeated by having a mouse bite his crotch. The girls are rather amused, while the boys all cringe and protest that it's no laughing matter.
Hostile Show Takeover — Referenced when My Melo is about to be cooked by the Monster of the Week, and Kuromi exults that "Starting next week, 'Pretty Lil' Devil Girl Kuromi-chan' will air in this timeslot!"
How Do I Shot Web? — Kuromi loses the instruction manual for the Melody Key, and has to figure out how to work it.
Living Toys — the Mari Land denizens may be sentient, but they are still dolls.
Lonely at the Top — Keiichi Hiiragi: dreamily handsome, incredibly rich, a world-class violinist, capable in the martial arts. He has no friends and no dreams.
My God, What Have I Done? — Kuromi does not realize her nightmare magic is bringing about the end of the world until late in the series.
In Shuffle, she was unaware her new Melody Key had any connection to the Dark Power because two pages in the manual were stuck together.
Nobody Poops — Aversion: Kuromi has to go to the bathroom in episode 9 and has a hard time going poop.
No Sell — Keiichi is resistant to Kuromi's magic through sheer willpower — and through visualizing himself being kissed by Baku.
In Shuffle, immunity to nightmare magic comes automatically packaged with being Bunny-Eared Mask.
Odd Job Gods — The God of Eggplants. He's an amazingly local god.
The One Guy — Kakeru Kogure, if you count just the main hero cast
One-Winged Angel Hiiragi Keichi gets one of these after he is possessed by the spirit of Dark Power near the end of the first series.
Origin Story — The fourth series Kirara★ sets before the events of the three anime itself. Explaing more about Kuromi's hatred to My Melody and the origins of the spirit of Dark Power.
Refusal of The Call — This is Keiichi Hiiragi's whole shtick in the second series, being forced to become a super hero as penance for his actions in the first.
Revenge Before Reason — Kuromi is motivated by the imagined slights and grievances, often very minor, she has suffered thanks to My Melody - she keeps a thick notebook on these. Given Melody is such a clueless Ditz, most of the grievances are better off laughed away.
Ridiculously Cute Critter — My Melody and all the inhabitants of Mary Land. Not surprising since My Melody was created by Sanrio.
Running Gag — Baku's resemblance to an eggplant is commented on by several characters, much to his indignation.
Shipper on Deck — basically every friend of Uta and Kakeru wants to ship them, including Jun Hiiragi, who has the hots for Uta himself.
Shirtless Scene — Whenever Kuromi opens a Dream Door in the first series, we see shots of Keiichi playing the violin while shirtless.
When he's about to begin playing the Song of the Dark Power in the series 1 finale, Keiichi just takes his shirt off first for no reason.
Shout Out — When the King is sending My Melo off on her quest, he refers to her as "Pretty Bunny Soldier My Melo" and "Earth Defense Bunny My Melo." My Melo later remarks that the King had been watching a lot of Earth TV shows at the time.
Sibling Rivalry — among Keiichi and Jun Hiiragi, and among their respective valets.
Sickeningly Sweethearts — one downright creepy, unnamed pair appear occasionally in the series. They always fall victim to Kuromi's mischief.
Tarot Motifs — The cards in the Melody Compact in Shuffle feature the summonable residents of Mari Land in different tarot poses. Notable is Rhythm as "The Fool," the King as "The Hanged Man," and My Melo herself as "The Magician." A few are even minor arcana - Bako is the "Four of Swords" and Santa Claus the "Ace of Pentacles."
Dar-chan: GYAHHH! W-what is the inside of this creature's heart MADE of?!
Two-Teacher School — the only teachers who appear with any regularity are Uta's class teacher, the female teacher he has a secret crush on, and the flamboyantly fruity music tutor.
Underdogs Never Lose — In at least four instances, a bottom-tier athlete/team wins against all the odds (The "Tiger" baseball team; a girl soccer team; a pro wrestler; and Kakeru)
The White Prince — Keiichi behaves awkwardly when Uta brings him to a greasy spoon; he even tries to pay the bill with a Black American Express Card.
Why Did It Have To Be Cute Things? — Mana has a severe phobia to cute things, which puts her in some unpleasant situations with My Melody.
Yandere — Kuromi, for both Keiichi and quite possibly My Melody. In almost every episode, she says she will gather Black Notes for Keiichi, something that involves turning the dreams of the depressed, the hopeful, and the occasional kindergartner into horrific nightmares, and at the end of season 1 seems quite willing to let the world be destroyed if it means Keiichi will like her. The only reason she joins up with My Melo is to save him. As for My Melo, she apparently wanted to be friends with her when they where little, then made it her life's mission to destroy her. The judge of Mari Land even states that her obsession is one of the main reasons she's being locked up.