This is based on opinion. Please don't list it on a work's trope example list.
Prepare to get scared Smurfless.
For the comic books:
- The Smurfs had their share of creepy adventures. The most disturbing adventures the Smurfs went would definitely be The Black Smurfs, where the Smurfs were being turned into evil black versions of themselves that could say nothing but "G'nap!", and bit each other on the tail to spread the infection.
- Worse was the ending of The Black Smurfs. Papa Smurf had been bitten after being reduced to the Last of His Kind. The only reason the Smurfs were saved from their extinction was cartoon physics, with the fire igniting an explosive substance the pollen being used as the antidote was shelved next to, and the explosion causing the pollen to spread across the village. Otherwise they'd all still be that way.
- The worst thing about the Black/Purple Smurfs is unlike the zombies they're loosely based on, they aren't mindless. One of the transformed Smurfs intentionally paints itself blue to make itself look like it hasn't been infected yet, allowing it to spread the infection in safety. Trying to stop The Virus is bad enough, but having said virus be smart enough that it can counter your lines of defense and mask itself among the healthy is so much more chilling.
For the Hanna Barbera cartoon:
- "The Smurfs Christmas Special": At least two examples:
- The climatic scene where Papa Smurf leads a rescue mission for two children, Gargamel and Azrael from an evil wizard, who conjures a wall of fire around himself, the kids, and the Ineffectual Sympathetic Villain, only to fade away screaming in defeated despair under the Smurfs' repeated singing of a sappy holiday song. The evil stranger, using his powers to make the fire grow and frighten the children adds to the scary situation.
- But none of that holds a candle to what The Stranger — his unofficial fan name — has in store for the children. Having kidnapped them in revenge for their uncle (a justice of the peace in their kingdom) always having thwarted his treacherous plans, he plans to take them away on "The Final Journey" through a Hellgate. When the children begin to cry and beg to go home, The Stranger accelerates his plans and insists that the children will like their new home. It is never explicitly stated what exactly he had in mind, but it is often implied by fans that he planned to do something incredibly and horrifically evil to the children that defied description. Even Gargamel and Azrael — whom are irredeemably evil themselves — are genuinely horrified to the point where they object ... only for The Stranger to force them to come along! The Stranger's plans are thwarted in the end, but the very thought of the fate the children were facing is downright frightening and bone-chilling, even for an adult cartoon but especially for a program aimed at pre-teens.
- The episode "To Coin A Smurf" has Gargamel actually succeed at turning three Smurfs (Brainy, Grandpa and Sassette) into gold coins. He was happily singing about it as he was headed into town considering how to spend them. Had it not been for him being mugged by a couple of robbers and the three of them being arrested, those three coins could have wound up lost in circulation or a vault somewhere, forever. To highlight how terrifying this is, the coins were fully conscious with the inability to act; they could all still see, hear, talk, and feel pain as several characters bit the coins to test if they were actually gold (which prompted them to go "Ouch" each time).
- First episode of season four, "Scary smurfs". Monster children abduct few smurfs as part of school project and turn them in monsters. It all turns out well at the end, but it is still very disturbing.
- Gargamel's goals were, originally, to either eat the smurfs in order to gain immortality, or use an alchemical formula to turn them all into gold. So, on one hand, he's trying to devour a sapient race for his own selfish goals, and on the other, he's trying to commit wholesale genocide to line his own pockets.
- The episode "Sir Hefty", involving a huge, Godzilla-esque, green wingless dragon terrorizing the Smurf forest and burning everything it came across with its fire-breath. The sheer destruction the monster causes in its wake is truly chilling, as is the fact the dragon is portrayed as one of the show's most threatening and genuinely dangerous antagonists.
- Imagine this from Laconia's perspective in the episode "Smurfily Ever After": you're a mute (and apparently deaf) woodelf girl who's about to get married to a very nice woodelf friend, and everyone in the forest (except for Mother Nature, who sent a calliope as a gift instead telling she couldn't come) is going to attend. All is well and dandy, and the wedding is going perfect. Then all of a sudden, the calliope starts playing terrifying music and ghosts start flying out of it, the scenery quickly shifts from sunny to outright dark, and everyone around you turns into mindless zombies that start walking towards the huge cauldron of boiling water located in the calliope with you unable to snap them out of their trance.
- One of the features that defines Nemesis is Facial Horror; following a curse being placed on him, Nemesis' face became so disfigured and grotesque that it horrifies other characters no matter how brave they are (only one of them being an exception). We never get to see the face itself, but what we do get to see instead is the back of his head◊.
- In "They're Smurfing Our Song", Gargamel talks in his sleep while Sassette and Brainy try to play Woody's magic panflute in an attempt to redeem him. In a way, and as evidenced by what he's saying, Gargamel dreams about torturing the Smurfs - right down to calling his catch a victim and questioning said victim whether they'd rather be simmered slowly or brought to a rapid boil (neither of which is pleasant).
- The griffins in "The Enchanted Quill". From what we are shown, they are incredibly aggressive creatures that are bigger than a human, bipedal, breathe fire like dragons, will chase after any and every trespasser they come across, and make some of the most horrible, shrill sounds in the entire show. They're also strong enough to punch and break through a door and they inhabit a large castle that's devoid of people. There's zero explanation for the latter.
- Gargamel's Villain Song from "The Blue Plague". It's mostly about Gargamel planning how to kill the Smurfs, but the absolute worst part has to be the very end of the song; the scene zooms into his mouth right out of nowhere as he looks towards the viewer in a disturbing, almost self-aware manner.
For the 2011 movie:
- Seeing Papa Smurf suffer while Gargamel is zapping him is a little unsettling. Smurfette calling his name doesn't help. Also, the scene where Gargamel starts capturing the Smurfs during the climax.
For Smurfs 2:
Other:
- In 2005, UNICEF's Belgian arm aired an ad as part of a campaign to rehabilitate former Child Soldiers in Burundi and the Democratic Republic of Congo, both former Belgian colonies. It depicts the Smurf village going through their usual, cheerful activities until they get suddenly bombarded by planes, bombs destroying their houses going down in flames, Smurfs panicking and running around in disarray, Papa Smurf running as quickly to escape the bomb (only to get bombed off-screen since we see his hat fly and land on a destroyed house), others getting crushed by the debris or the explosions, lifeless bodies laying around among the ruins, Baby Smurf crying in utter confusion and terror... it all just screams War Is Hell! There's a good reason why the ad print serves as the trope image for Sugar Apocalypse! It's also a good thing it was only aired after 9pm to prevent most children from seeing it!
- The Smurfs: Mission Vileaf, while otherwise perfectly tame, makes Gargamel actually terrifying - without even really changing him that much. The game has you play from the perspective of several Smurfs and has Gargamel walk close to you during regular gameplay (i.e. outside of cutscenes) in the Gloomy Swamp. What makes this scary is that you're on ground-level or close to it, letting you have a really good look at just how large he is compared to you (and he's huge), his footsteps make sound so you know he's there even if he's not on-screen, and the swamp's already creepy ambience (namely dimmed lighting and foggy weather) makes him seem like a giant monster lurking through the darkness that you absolutely don't want to attract the attention of. Can be seen here.