Despite the anime's cutesy, blocky style, it's called Gregory Horror Show for a very good reason
- Hell's Chef, generally agreed by the fans to be the most frightening character. And for good reason, considering his glowing red eyes, almost unstoppable rage-especially if you're a smoker-, and bloodied knife that can cut through elephant bones.
- Lost Doll is this way with her evil side, especially considering how she just flips at the screen.
- Gregory as his half-burnt, zombie-like self.
- We also see his mother and James and they don't look so good either.
- TV Fish is generally the most benign resident of Gregory House in that it doesn't outright try to kill or harm anyone. But it also projects memories of those it comes in contact with, particularly painful memories...
- Neko Zombie may not be especially scary at first glance, but what was done to him is pretty horrific: someone (heavily implied to be Gregory) sewed his mouth, ears, and eyes shut and chained him up in a room in Gregory House, leaving him half-starved most of the time. It's even worse seeing as he's one of the few truly benevolent residents of the hotel.
- There's something about Judgement Boy that just makes him downright unsettling, despite him being one of the least dangerous residents. He just looks creepy, and his appearances in the series usually are signalled by a Drone of Dread seemingly caused by the glowing love and money symbols he carries and the Hell Is That Noise of his singing combined with the clanking of his moving along his rail. Not only that but at first all you can see is the glowing of his symbols coming closer and closer as you hear his clanking and singing. His brief appearance in the second episode of season 1 can catch you off-guard if you haven't seen him before and aren't aware he's going to cameo here.
- Hell, Gregory himself can be pretty creepy. He loves to just appear when he wants to and with no warning. And that's not even getting into why he's keeping guests here in the hotel or his ghostly form.
- His mother of course is a whole new ballpark. Gregory Mama is a vain woman who only has one goal: Drink the souls of those who end up in the hotel to keep herself young. Gregory is terrified of her and for good reason.
- The Dead Bodies will go from having a nice chat with you to trying to steal your body in a drop of a hat.
- The Poor Conductor will gladly try to skewer anyone who hates his music. Even if you had agreed to give him a chance he will still try to kill you.
- Just the fact that none of the guests we see really did escape Gregory House is pretty terrifying on it's own. This is a place that no matter what you do, you will always return to Gregory House.
- Hell's Roulette is Mario Party on crack! With a host who really seems a bit too excited for others to play his game, without any of the skill and add in the fact that you will likely be getting hurt is there any wonder why Gregory gets scared when he has to play it?
- The warp Gregory goes through in the Last Train. First he sees a version of his mother asking him to open his eyes before eating him. Then he thinks it's over until he sees a bunch of lost souls in the train. Before he can fathom why they are there, he sees another him who gives him some keys. After the warp ends for good, Gregory wonders if he has to return to Gregory House as the episode ends.
- Oddly enough, Gregory's angry breakdown he has in the third to last episode of the ''Last Train'' is pretty chilling. It might be in part because of how well his voice actor emotes the rat's anger from not being able to enter the Lost World.
- While epic at the same time, the boss fight with Gregory Mama in the game is this as she at first laughs evilly as she pelts the guest with fireballs only to become more angry as the door breaks down.
