Anvilicious: Shin Pet Shop of Horrors on motherhood, so much...!
The original series revolves around love of some form (romantic, family, friends, ext.).
Designated Hero: For a given value of "hero". D's attempts at teaching people a lesson might be justified as Laser-Guided Karma... except he's also been known to get innocents killed as well, such as that fiasco with the rabbits.
Development Hell: The mythical live-action movie...; considering other anime/manga-to-Western-movie transformations, though, this might be for the best.
Nightmare Fuel: The extra story about D's experiences with the Holocaust. Most of it is shown through his interactions with Eva Braun, but it's incredibly creepy what all is implied, especially if one knows what really was happening. And then, there's the scene at the end where Eva rides her pet Kirin to be reunited with Hitler. When the Kirin tells her that the lights she sees are from Germany burning and "the deaths of millions of Jews" and that Hitler was the cause of it, she just smiles and says "How... beautiful!"
"Eva Braun got her wish. She was the Devil's wife...for two days." Brrr...
In one story, a couple who recently lost their daughter are sold a pet rabbit that looks just like her. Because the daughter look-alike smiles and pleads for candy and cookies, they feed them to her, even though D specifically tells them to only feed her vegetables. Upon eating the cookies, the rabbit begins binging on more junk food, until two smaller rabbits burst out of her stomach.The story then cuts to a couple of children playing in a park, until they realize that they're surrounded by some hostile-looking rabbits. It turns out that the rabbits spawned from the first one will keep eating everything they can (including people, making the fate of those children pretty horrible to think about), and the police get countless reports about rabbits attacking people. Meanwhile, the police find the wife who adopted the first rabbit, severely injured and in shock from watching her husband die in front of her. We then find out the fate of their actual daughter - they indulged her constantly until she became a shoplifter and a drug addict, eventually dying from the latter habit.
A model seeking a shortcut to weight loss is offered a "diet pill" by a glamorous fellow model... which eventually causes her to shed her skin and transform into an insect creature right smack in the middle of the Uncanny Valley. It's made especially effective by being set up in contrast to one of the more heartwarming stories.
Replacement Scrappy: In Pet Shop Of Horrors: Tokyo, some fans are less than enchanted with Leon's replacement, Wu Fei. Most fans seem to agree that even if they like Wu Fei, they'd still rather have Leon back.
Wu-fei is becoming a Chew Toy: either Matsuri Akino dislikes him too, or she's just pleasing the audience that misses Leon so.
They Just Didn't Care: A page in Tokyopop's release of volume 4 is full of Õs where apostrophes should be. Subsequent pages also have a few instances of this.