- Pisces Dementia. It just seems funny at first, but keep in mind that if they'd eaten a single piece of fish while in that condition, they'd have been trapped as babbling fish-craving maniacs forever. And if Rico had eaten the herring, nobody would have been able to stop them. Brr. Lucky break there.
- When you see Skipper sink into the ocean after his memory is erased, you see him pass out rather quickly. You start to drown when you start breathing in water, which happens after you pass out. They made us watch Skipper, one of the penguins we've grown to know and love, slowly die. Or not, but still watch that scene with that in mind.
- Kowalski in "Brain Drain". The things he says are funny, but at the same time he comes across as quite scary-looking, as though he'd been lobotomized.
- In fact, any time he goes insane, it's scary.
- In "Byte-Sized", the Penguins can hear Maurice shouting from the lemur habitat, "I can't stand it anymore! AAARRRRGGHH!!!" So they go to the lemur habitat to see what happened...and then see King Julien covered in what looks like blood, lying motionless on the ground. The dialogue here isn't very comforting either.Penguins: *look on in disbelief*Mort: WHY?!?Maurice: You've messed with me for the last time!
- Marlene when she's out of the zoo.
- Good God, the rotten Lychee nuts from "Kingdom Come"! According to the show, if anyone eats red Lychee Nuts when they're rotten, they cause their consumer to develop red eyes and go freakin nuts to say the least. It was kind of funny when King Julien was under their influence, but with Maurice? Not so much. He loses his mind, establishes a dictatorship in the zoo, and even outsmarting the penguins when they tried to cure him. Fortunately, the day gets saved by Mort of all people.
- After a heartwarming moment where King Julien and the penguins forgive Maurice and told him that the nuts were the problem and not him, we pan down to see that Mort is eating the lychee nuts, Laughing Mad as the episode cuts to black. Just imagine how many people lost their appetite for lychee nuts after they saw this episode.
- Dr. Blowhole tried to freakin' drown the world by melting the glaciers in the polar regions.
- Rico's violent behavior from when he switched bodies with Roger the alligator.
- Skipper is even disturbed when Rico doesn't follow his orders to stand down.
- For the love of God, do NOT go out of your way to sate Rico's explosion obsession. Julien learns this the hard way.
- The first time the penguins meet the sewer rats. Those glowing eyes...
- Savio the boa is a Knight of Cerebus who even got the penguins genuinely frightened (including Rico), and who has yet to be defeated by the penguins themselves, who had to rely on outside interference several times. The worst part is that he is as intelligent as he is polite.
- His debut episode has him eating almost everyone, and he would've continued his rampage had it not been for Burt the elephant.
- One of the first episodes had the main characters go to meet the new neighbors that just arrived, only to meet no one but a dark cage with nothing to be seen nor heard. What happens is that Marlene, the penguins, and the lemur trio all, one-by-one, get stuck and carried away by long, sticky tongues that come out of the darkness. We don't really see who's tongues those were until the end, which were only harmless and cute chameleons.
- The snakehead, it sounds like some imaginary fish, but it is very real.
- Skipper's zombie appearance in "I Was a Penguin Zombie" through a combination of topical cream, which affects his speech, causing him to speak gibberish, applied to his broken wing, talcum powder, getting tangled up in gauze, and a sprained ankle. The only word we can understand in his gibberish that has the Penguins, who mistakenly believed Skipper died, running from Skipper for the majority of the episode? "Brain."
- Rico's Roaring Rampage of Revenge in "Marble Jarhead" after Julian, Maurice, and Mort take his doll, thinking she's a princess (long story). To elaborate, right after the lemurs leave, Rico goes apeshit and trashes the entirety of Kowalski's lab in a mad rage. And then, when he finally catches Julian in the toy store, he dismembers the male doll that he's talking to and threatens to beat him with its leg to get his doll back. Maurice's reaction sums the whole thing up perfectly:Maurice: Now that's just disturbing.
- Rico accidentally swallows Kowalski in "Private And The Winky Factory". Private and Skipper joke at first that he's eaten too much candy, then watch in unabashed horror as Kowalski battles his way up out of Rico's gut.Kowalski: (eyes wide) The things I have seen...Rico: Bad Meow-Meow... (passes out)
- The way Kowalski plays up Graveyard Eight in his song. There's a ghostly bus roaming through New York and nobody knows where it came from, all that's known about it is that it leads to death of many animals. Sure, the ending reveals that it's just a regular bus. But still, the myth had to come from somewhere, which means that Graveyard Eight did kill a few animals... and despite Rico and Fred being there to make the song lighthearted, the atmosphere of it is quite creepy, with Kowalski being dead serious while singing it, as well as the purple and green background.
- Kuchikukan. Despite being somewhat comedic at times, he's still a world-destroying Eldritch Abomination who came very close to obliterating the Earth in his sole appearance.
Nightmare Fuel / The Penguins of Madagascar