Starting off with the man/mouse himself, this skeevy old rodent is the owner and caretaker of Gregory house, boasting an eerily intimate knowledge of its guests and an ambiguous level of influence over their fate. At times, he seems like just another sadistic crackpot damned to the purgatory of the house, while at other times, he comes across as the true mastermind behind its paranormal activities, answering only to his crueler, more menacing mother. Word is, Gregory is actually a manifestation of the shattered hopes and dreams of his own guests, which seems weird at first, but if that's going to look like anything, I guess it may as well be an aging rat.

Apparently a pink gecko, Nurse Catherine is one of the house's most prominent and feared denizens, operating a medical ward where her patients only ever leave a little bit deader. We never learn a thing about her past, but she seems pretty comfortable working as a nurse for unkillable ghouls and revenants, demonstrating an almost (okay, blatantly) fetishistic lust for draining a "patient's" entire blood supply with her oversized syringe.

Though he constantly sings "Do you know, who I am? They call me Judgement Boy," this demonic set of scales is one of several identical beings with a unique gold-plated leader. They travel the house on a rail system, originating from a strange place known only as "the judgement factory." They never seem to harm people, per se, but they do quiz guests on difficult moral choices that may or may not reflect their actual past sins. They're as creepy as they are lovable!

I love this guy's candle-hat, and you can never go wrong with glowing eyes in a faceless hole. Hell's Chef is another of the house's star players, a belligerent old butcher who loves to turn guests into gory new dishes...sometimes feeding them back to the same guests. Luckily, he "shuts off" if his flame is blown out, though apparently not for long. He's one of several monsters that Catherine has shown romantic interest in, apparently providing him with many of his best ingredients.

It figures as much that Death itself would hang around Gregory House, and it's perhaps not surprising that he's the least dangerous, most reliably helpful thing there, usually siding with guests and working to put the house's monstrous residents to a proper rest. He's also Jamaican, in most translations, like all of our culture's most adorable Grim Reapers.

This cutie patoot is said to enjoy performing unnecessary surgeries on guests as they sleep, and somehow transferred his own brain into his current custom-built body. He's technically Catherine's boss, as we see in the fourth animated season, but constantly used, abused and terrorized by her in myriad ways.

This chlorophyllic bandito has an almost "heroic" personality, but that's not saying much; he just sort of thinks he's always doing the honorable thing, even when he's challenging people to shoot-outs for ridiculous reasons or pursuing "romance" with the inappropriate tenacity and disrespectful persistence of Pepe le Pew, only covered in thorns, so a whole lot worse unless you're really into the weird stuff.

Though marginally less insane than her older brother, Cactus Girl is a straight-up bandit, lassoing people and robbing everything on them, especially clothes, apparently embarrassed by her own wardrobe. In the fourth animated series, she eventually becomes a nurse working under Catherine, which is kinda cute. A cactus nurse really seems like it's more up Gregory House's alley.

I love that rotten, drippy face on this guy. "Dead Body" apparently went out in a drunk driving incident, and is still perpetually intoxicated in death, demonstrating unpredictable mood swings depending on the availability of more booze. The series alternates between treating him as a unique character and using his model for whole hordes of undead, and I like to think they're all ghost-drunks.

Hilariously, this murdered cartoon dog constantly complains about an "inexplicable" headache, and constantly pesters Catherine about various pains and ailments both real and imagined, all of which he seems proud of and enjoys describing in great detail. Otherwise, he seems fairly harmless.

This little guy takes after his dad in almost every way, but his eagerness to be helpful to everyone makes him a bigger threat, as the first thing he'll usually do is fetch one of the others, especially Catherine, to "assist" a guest in need. He also has a very, very briefly-seen mother with a fashionable carnivorous plant growing out of her head.

This creepy, dead child apparently just wanders the halls of the house, crying and begging for the lost dollie she doesn't realize her soul is already imprisoned in. She's even got a creepier doll-face on the back of her head! I love how almost every one of the Gregory House residents could easily carry their own individual horror movie.

There's not much to say about Trap Mouse, a killer robot built and controlled by Gregory, but he's got a prettty cool design, with giant steel jaws as "ears." In the series, it's specially constructed to hunt down and maul their latest guest, in one of Gregory's more explicitly malicious moments.

This cute little guy tries to help guests fall asleep by counting his own jumps, but invariably puts himself to sleep instead, then unknowingly invades nearby minds in his dreams. This results in Sleepy loudly muttering people's innermost secrets, shameful thoughts and repressed memories, unraveling some of the reasons why they've found themselves lost in a hellish nether-realm of psychotic cartoon animals.

This archaeologist is madly obsessed with uncovering fossils, to the point of forgetting his wife's death and just sort of ignoring his own, eternally questing for more specimens. According to the board game, he's capable of turning people and animals into instant fossils for his collection.

This aging, alcoholic "master of time" only appears in the shorts and the video game, able to warp time to a limited degree by winding himself backwards or forwards. Like an alarmingly large number of the other monsters, he's another alcoholic with a perverted streak. I guess that just goes hand in hand with being a big enough dick to end up in Gregory House.

"My Son" is the official name of Clock Master's child, though maybe his dad just calls him that so often they've forgotten his real one. The two are fiercely defensive of one another, sharing such a close bond that in the video game, My Son even carries his father's soul. The perpetual bloody nose is an interesting, somewhat unsettling detail...he doesn't even seem to have clock hands. Were they torn off? Does his dad beat him up? Or, considering this is a Japanese series, is he constantly aroused? None of these are wholesome possibilities.

This monster-child constantly begs people to spin his wheel, subsequently transforming his whole surroundings into giant, deadly, supernatural board games. I like how that dumb, drooling face implies a brain completely addled by gambling and gaming. If only somebody would smuggle in a 3DS, he might leave everyone alone for a while.

This bleeding, skeletal samurai apparently just wants some direction, since he'll swear his undying alleigance to just about anybody and defend his new "lord" to the undeath - at least until someone else comes along to fight for. You know how fickle skeletons can be. I do, anyway. I don't want to talk about it.

This poor hollow bastard is said to be the final form taken by all those who lose sight of friends, family and personal identity as they succumb to the corporate life, an even bigger cultural issue in Japan than just about anywhere else. Haniwa Salaryman spends his afterlife in Gregory House under the constant delusion that he's on some kind of important business trip. He had a different name for the board game that I can't seem to recall, and his original character art seems to be absent.

Oddly enough, the bonsai tree growing out of this guy's head has very little to do with his powers or behavior. Instead, his claim to fame is his psychic third eye, which somehow reveals the most private fantasies of anyone who looks into it. He especially enjoys the really dirty ones, and getting completely plastered on sake. I'm really noticing a pattern here. Are all these monsters just facets of Iwata's dad or something?

A set of deranged brothers known as Black Duck and Black Duck 2, these razor-toothed waterfowl operate a broken, deadly roller coaster called "Speed Mouse," apparently doing regular "maintenance" to make it ever more broken and more deadly.

More prominent in the video game than the animation, Devil Dog usually appears at first in the guise of an angel, only to reveal her true form and rough you up with her pitchfork. She can also manifest a door that will lead to either heaven or hell, depending on where you really belong, and assuming you're sick enough of Gregory House to take the chance. I can't imagine why, it doesn't seem like it ever gets too boring.

We never hear this guy's story, except that he was at one time an anthropologist. Now, he wears an ancient shamanistic headdress and never stops dancing a hypnotic, ritualistic dance. Anyone who witnesses the dance is unable to resist joining in until they finally drop dead.

Egypetit is an interesting one; in the board game, it's a cursed mummy that attempts to change places with the living. In the animated series, it's not the corpse inside the sarcophagus at all, but the sarcophagus itself, which rants and raves about the day it can awaken the "dark master" it carries inside.

This adorable warty hag is unpopular with her clients for two reasons: first, all of her predictions are horrible, and second, they always come true because she makes them come true. Awww! I especially like her two little fangs. There actually is just one frog that has those; the Budgett's frog! I doubt Iwata was putting that much thought into it, but it would certainly suit her.

These cute little guys are described in the board game as a pair of twins who dreamt of becoming actors, but the animated series shows dozens, possibly hundreds of them as a shadowy work-force, running and maintaining Gregory House in the background! They seem to be particularly affiliated with the Judgement Boys.

This undead cat gets about the level of treatment you would expect in a haunted house ruled by mice; he's kept locked away, starving in a very small cell, every orifice stitched shut by "someone" who is never revealed but was probably Gregory. He will, of course, jump at any opportunity he can to maim and devour one of the rodents or pretty much anyone else in his path.

How hilarious is a big fat guy with the word "CHOLESTEROL" on a t-shirt? He's really speaking my language. Fat Chicken is only briefly seen in the animated series, excitedly bragging about his new job at the Chicken Factory, which probably isn't the first time he's gotten that particular "new" job, going by how Gregory House usually operates. In the board game, he supposedly just wanders the house eating everything and everyone he can get his feathers on, which is honestly one of the scariest freaking things here. The fact that it's a big, dumb cartoon chicken just makes it so much more nightmarish.

A strange, unseen being inside of a large mirror cabinet, Mirror Man, as you may have guessed, can show guests the "truth" in their distorted reflections. He can also open up and walk through any mirror, as if it's just a door.

This might be my favorite monster, which is probably predictable considering it's also the least humanoid. It's also another one alternately treated as a unique being and shown as an entire "species," which "swim" in a ghostly realm under the house foundations. They're timid and nonviolent, but their television screens tend to play back past events that viewers may not really want to be shown.

Everything about this guy is frightening. The occult robes, the single bleeding eyeball, even the little pink heart on his shirt. Fortunately, he's far from the relentless killing machine he resembles and closer to an inept, crazy goofball, performing dark necromantic rituals in a decrepit church that apparently never actually accomplish anything. How cute is that?

Yes. Toilet Baby. We'll end on what's obviously the most terrifying thing in the series, a wailing infant with bloodshot eyes and a toilet paper dispenser for a face. The toilet he haunts even seems to be a separate being, with its own set of feet, and periodically flushes him down - especially after the baby has latched on to someone else with his toilet-paper tongue. The best part? Toilet baby has been shown screaming for help as he's sucked down the commode, even as he drags his victim down with him.

Yeesh. The idea that they can just come back after you've flushed them...I would be in so much trouble.