When playing a game like Dead Space or Silent Hill we’re prepared to be scared, to see creatures that will haunt us till our dying days. But we believe, as gruesome as those monsters can be, some scares can be even more intense when you have a false sense of security--like when exploring the candy-coated worlds of kiddie games. The following creatures all disturbingly undermine the adorable worlds they inhabit, giving unsuspecting children (and adults) nightmares for years…

One of our earliest scary memories in gaming dates all the way back to the whimsical, Arabian Nights world of Super Mario Bros 2. We were already off balance thanks to how different the game was from the original Super Mario, but when we went to pick up a much needed key, we were in for something even more unexpected. A seemingly decorative mask on the wall came to life and began chasing us, not stopping until we were dead. Its name was Phanto and it hated us with a passion. The empty gaze of the disembodied mask was troubling enough, but its everlasting thirst for our blood made it unforgettable.

We anticipate killing emaciated zombies in pretty much every game these days, but that wasn’t the case when we entered the fantasy world of Ocarina of Time. We were prepared for dragons and goblins, not slow-moving corpses that could freeze you by just by looking at you. The cadavers then wrap themselves around you in a far too suggestive manner, biting you until you die. For extra weirdness, wearing certain hats in Majora’s Mask makes the corpses dance, which keeps Link physically safe, but no doubt gave him permanent mental scars.

Rare is known for sneaking grown-up jokes and references into their kiddie games, whether it’s a rude pun in Banjo-Kazooie or animal sex in Viva Piñata. Donkey Kong 64 does the same with its Mad Jack boss fight, a starkly lit battle between a small ape and a giant, cackling Jack in the Box. Mad Jack’s propensity for laughing in a Donald Duck voice should’ve made him less threatening, but when he starts doing that with a missing eye, he becomes even more off-putting.

Kirby’s world might just be the cutest, friendliest world in all of video games, like dozens of hugs plastered across your TV screen. But that world isn’t all smiles, as the demonic Scarfy taught us many times. His smiling face looks inviting, but try to eat him and he becomes a sharp-toothed, one-eyed demon. Scarfy’s lethal intent is frightening enough, but we’re more troubled by his seamless shift from potential friend to murderer.

On the surface, Ecco the Dolphin for Genesis was the kind of environmentally friendly celebration of nature that was all the rage in the early 1990s. But Ecco’s quest to save the Earth ultimately brings him into contact with a floating alien head intent on stealing Earth’s resources. Made all the more intense thanks to Ecco’s tricky controls, the eerily quiet battle ends with the weird head gradually ripped apart by Ecco’s sonar waves, a visual we hardly expected based on the game’s relaxed opening levels.

Retro Final Fantasy games are filled with weird bosses that could make this list--creatures with malicious intent that don’t fit their cute, pixelated exteriors. But since we have to limit ourselves to one, we’re going to go with Calcabrina from Final Fantasy IV. Not only is she the archetypal undead doll that has vexed children for centuries, but you only fight her if you can’t prevent two weaker enemies from fusing together. The lurking threat that she could appear when you’re least suspecting it puts her over the top in this unnerving contest.

Pikmin is just a disturbing game in general, mostly due to the series’ commitment to finding horrifying new ways to murder your army of ant men. Most Pikmin bosses in the games straddle the line between goofy and threatening, but optional boss Smoky Progg is decidedly on the threatening side of the equation. An ethereal, frogish thing made of poisonous gas, Progg is so intent to kill Olimar and his friends that he will actually camp at your base and eat your unborn Pikmin! Nature doesn’t get much more brutal than that.

The franchise has a tradition of Ghost-type Pokémon that are freaky on the outside and even more scary when you read their Pokédex entry, and fifth gen monster Yamask is one of the most recent examples. A ghost carrying around blank mask, according to his description, "Each of them carries a mask that used to be its face when it was human. Sometimes they look at it and cry." Yeah, think about that the next time you capture him.

Did we miss any other great examples of hideous monsters creepy into cute games? Share your harrowing experiences in the comments!

Need more gross bad guys? Check out Resident Evil's most vomit-inducing foes and Silent Hill's 13 creepiest enemies.