Two Belgian cartoonists were sitting at dinner one day and the one said to the other, or at least tried to say: "pass me the salt!" But he couldn't remember offhand the word for salt in a senior moment and instead made up a word to mean "whatsit" or "thingamajiggy" - "schtroumpf" (sh-troompf). The other cartoonist jokingly said back "Sure, I'll give you the schtroumpf, but when you're done schtroumpfing, schtroumpf it back afterwards." What followed for the rest of the weekend was an inside joke with them replacing verbs with the word "schtroumpf" and the trick of maintaining meaning but still using that replacement word would come in handy later.
The cartoonist with the momentary apahsia was "Peyo", the nom de plume of Pierre Culliford, who produced a comic for "Spirou" magazine called "Johann et Pirlouit". It was a medieval sword and sorcery strip, and as such occasionally ventured into magic. Little blue characters with strange caps appeared in one story in 1958 and were a huge hit, leading to a spinoff.
And by "huge hit", that's actually a severe understatement. They were popular enough to warrant their first book, a story about the "schtroumpfs" (later Smurfs in Dutch and English) being infected and turned into zombie-like blackened parodies of their former selves who transmit their contagion by biting each others' tails. Soon the wizard Gargamel and his cat Azrael were introduced, with the Smurfs turning out to be part of a mystical alchemical formula to turn base metals into gold. The general characteristics of the species and its culture were fleshed out pretty rapidly, and became a children's fixture about tiny magical creatures living in a wholesome collective, their homes having been fashioned out of mushrooms. Their leader was an aged gnome named "le Grand Schtroumpf" (the Grand/Head Smurf, translated into English as "Papa Smurf") with his distinctive red trousers and cap, but for the most part they were a happy-go-lucky collective going about their lives engaging in their own interests. There was a "Schtroumpf costaud" (heavyset Smurf) complete with tattoo and dumbbell, a "Schtroumpf farceur" (joker Smurf) who liked to give people elaborate wrapped boxes which exploded in their faces (harmlessly) and so forth.
The French speaking world went crazy for it in a second wave in the 1970s, and books, small PVC figurines and other collectibles flew off the shelves. A German company made tracing stencils that allowed you to draw your own Smurfs, small fingers being relatively unable to copy the characteristic swooping lines of Peyo's rendering of their Phyrigian caps. Whereas the books identified a few Smurfs by occupation or interest, toys included non-canonical figurines such as an astronaut smurf complete with helmet, one with a gold lamé outfit (Disco Smurf?), an archer Smurf, a pipe smoking Smurf, and so forth. Most weirdly there was even a novelty record with "Father Abraham and the Smurfs" - turns out "Father Abraham" was not some kind of Hasidic rabbi but just some Dutch singer with a really long beard and a penchant for black hats, singing very simplistic 70s Eurovision type songs with a bunch of sped-up voices accompanying him, a similar gag to Alvin and the Chipmunks. A promotional single sold out in the first day, so a full album was commissioned, thrown together hastily, and sold really well, leading to a bunch of people digging into their parents' old record collection and finding one of the weirdest concept albums imaginable.
The English speaking world found out about it in the 1980s, and there was yet another wave of Smurfmania, this time complete with an English-speaking Saturday morning cartoon, another round of PVC figurines, and so forth. The books were translated into English and sold fairly well, and the world became awash in blue. There were breakfast cereals and lunch boxes, and the franchise made a killing.
Interest in the creatures waned until the 2010s, with the introduction of a 3D animated/live action hybrid CGI film, starring Simpsons voice over artist Hank Azaria as the evil wizard Gargamel.
The books follow the peculiar French habit of having hardcover-bound comic strips in collections but in a format that can be enjoyed by children but also by adults. The children appreciate the brighly colored, primary-hued tales of the tiny creatures living in mushrooms, but politics and more adult themes found their ways into the storylines. Turns out there is a North Smurf village, and a South Smurf village, complete with subtle differences in the use of the word "smurf" (the title of the story is "Green Smurf vs Smurf (who is) Green") and is eerily reminiscent of language tensions between the French and the Dutch in Belgium. The bonhomie and happy times in Smurf village are jeopardized when Gargamel makes a Smurf (by this point he is past the idea of using one to make gold - he wants to hurt them all, badly) and so decides to disrupt their all-male commune with a female Smurf. When she arrives, plain and brunette, she's seen as obnoxious and a problem and is ignored, but when transformed by Papa Smurf's humane use of magic and a nicer dress, they start competing over her and treat her like a sex object. I'm sure there's at least one feminist thesis on this story.
But probably the most inadvertent political overtone came in from "The Black Smurfs" - the first story. The notion that when stung by a certain kind of fly a Smurf turns into a non-intelligent, violent, illiterate, near-mute Hodor that seeks to literally bite others in the ass, infecting them with their own disease tripped all kinds of "what's that supposed to mean" concerns, especially after the outright racist horror that was Tintin in the Congo. When reissued for US television, the story was changed to the Smurfs becoming purple, to avoid any racial connotation, explicit or implied.
But it's hard to have any real problem (apart from some rather disturbed US political commentators) with the notion of a happy community in which everyone pursues his own interests and humors his fellow Smurf. (By now I think they've all figured out that presents explode, so they obviously keep opening them just to make the Joker happy). The little blue creatures are nearing their 50th year, and by now they're practically an institution.
Should you find any in a closet and they're in fantastic shape, do be advised that even the most pedestrian looking ones can be rare and extremely valuable, but given the nature of PVC the chances of that are rare.