Little. Yellow. Different. Better.

Pokémon, that most enigmatic of all—well, what is it? A game? TV show? Toy?—claims the Top 5 spots on the U.S. video games chart. It is the top-rated kids’ TV show; more than 50 million Pokémon game cards have been sold; eBay is hosting more than 5,000 auctions for Pokémon cards; Burger King is distributing 57 Pokémon toys over 56 days—expect chaos at the drive-thru. Pokémon: The First Movie, which opened this week, will rule the fall box office. When a Los Angeles radio station announced a contest for free movie tickets, 70,000 calls a minute overwhelmed the switchboard. Pokémon creator Nintendo and its licensees will make $1 billion in the United States from Pokémon this year and $7 billion worldwide.

In the happy months before Pokémon dolls are chucked into the Toys “R” Us remainder bins with Trolls, Pogs, and Ninja Turtles, let us pause to reflect on the lesson of the Pokémon billions: This money could have been yours.

In 1994, anyone could have known that Pokémon was coming. This is the Iron Law of Preteen Manias. Every four years—every mini-generation—an entirely predictable entertainment phenomenon enthralls America’s kids: Transformers in the mid-’80s, Teenage Mutant Ninja Turtles in the early ‘90s, Mighty Morphin Power Rangers in the mid-’90s, Pokémon today.

These phenoms invade from Japan—or, in the case of the Ninja Turtles, might as well have. They are premised on the notion that some mysterious force can alter the ordinary into the extraordinary. Kids, especially 6-12-year-old boys, strongly identify with the changing characters, imagining themselves as suddenly potent Transformers, Turtles, or Power Rangers. With Pokémon , they become masters of the evolving, growing Pokémon monsters. These games/toys/shows present kids with a world they can control–a world where the little guy becomes conqueror, kids (or their proxies) defeat evil, and adults are essentially absent. These entertainments, in short, serve as practice for growing up, preparation for the trek through adolescence.

Pokémon outclasses its predecessors in every way. Introduced in Japan as a video game in 1995, it now features a card game, several video games, a TV cartoon, and endless related foods, books, posters, toys. (The cartoon made headlines in December 1997 when its flashing lights sent more than 700 Japanese kids into convulsions.) The games and show arrived in the United States a year ago and became wildly popular almost immediately. They are a triumph of cross-marketing. The TV show essentially advertises the games, which pushes sales of Pokégear.

In Pokémon, you play a “trainer” of “pocket monsters”–cute, curious creatures with magical powers. The most famous Pokémon is Pikachu (Gesundheit!), a delightful little yellow mouse that shocks with its electric tail. Butterfree blows “stun spores” with its butterfly wings. Bulbasaur is a squat blue dinosaur with a plant on its back. Other Pokémon are similarly odd. (Click here for more about the cleverness of the monsters.) With care and training, Pokémon can “evolve” into more powerful creatures. Pikachu, for example, evolves into the thunderous Raichu. (Pokémon may be the only way to keep Darwin in schools.) As zookeepers for this freakish menagerie, kids are supposed to collect all 151 Pokémon, store them in little Pokéballs, and use them to fight other players’ Pokémon.

Pokémon combines the best elements of other kid fads including Beanie Babies, Tamagochi, and Ninja Turtles. Like Beanie Babies, Pokémon exploits kids’ instinct to collect. From baseball cards to dolls to stamps, preteens are collectors by nature: They are learning to recognize patterns and organize their world. Pokémon allows them to indulge this in the most elaborate way. The motto of Pokémon is “Gotta catch ‘em all.” You have to get every Pokémon card and play the video games till you capture all 151 Pokémon. (Ninja Turtles or Power Rangers lacked this collecting aspect.) This acquisitiveness has turned Pokémon into an economics lesson: Kids spend hours bartering cards and figuring out what exactly a particular Pokémon is worth.

Pokémon marries collecting to pop cultural obsession, catering to the interests of preteen boys. There are dinosaur, snake, and dragon Pokémon. Several were created by DNA experiments gone awry. Some practice martial arts. One is made out of computer code (don’t ask).

Pokémon softens its violence with sweetness. Like Ninja Turtles and Power Rangers, Pokémon is packed with battle scenes. But it is far gentler. Pokémon never die, they only “faint.” They are warriors, but they are also darling. “They are cute fuzzy things, but they are also really violent. That is incredibly appealing to kids, especially boys,” says Susan Linn, associate director of the Media Center of Judge Baker Children’s Center. Pokémon plagiarizes Tamagochi, the nurturing game that so entranced kids. Pokémon demands that players learn to care for their charges, educate and “evolve” them, and take them to the Pokémon hospital when they are hurt.

What differentiates Pokémon from other phenoms is that it merges a TV franchise with a compelling game. Transformers, Turtles, and Rangers were largely confined to action figures and television. Pokémon, by contrast, centers on an intellectually demanding game. (It may resemble Dungeons & Dragons more than any toy fad.) Pokémon creates an entire alternate universe, a land with its own cities, ecosystem, and rules. It is essentially a genius-level version of rock-paper-scissors. Each Pokémon has its own skills that work better against some Pokémon than others. Trainers calculate how their Pokémon’s talents match against rivals, a fiendishly complicated task that requires mastering and manipulating information about every monster—a 151-variable algebra problem. Can a Sandshrew, a specialist in ground fighting, beat a water Pokémon like the Poliwhirl? Can a Pikachu defeat an evolved Raichu? (Yes, if it uses speed attacks rather than electrical ones.) Many adults, delighted by the game’s complexity, have taken up Pokémon. No adult ever played with Ninja Turtles or Power Rangers.

Pokémon has caused the expected consternation among parents and educators. Its emphasis on acquisitiveness annoys parents who find themselves buying pack after pack of new cards. Pokémon has been banned in countless schools because kids won’t stop trading cards. Parents find themselves intervening to stop their kids from making bad deals with unscrupulous classmates. Critics claim Pokémon is literally addicting kids. A San Diego law firm just filed a class-action suit against the Pokémon card manufacturer alleging that Pokémon is illegal gambling. By seeding packs with a few high-value cards, the manufacturer is encouraging kids to buy Pokémon cards like lottery tickets. Kids buy again and again in hopes of finding that rare holographic Pikachu.

TV watchdogs complain about the cartoon’s violence. (The TV show, it must be said, is far less interesting and sophisticated than the games.) And Pokémon has spawned the usual fundamentalist protests: One Colorado preacher made kids in his congregation watch as he torched Pokémon cards and chopped a Pokémon toy with a sword.

But critics can rest assured that Pokémon won’t last. The market will saturate. Kids will tire of the 151 creatures and even the 100 new ones on the way from Japan. Sure as the Backstreet Boys will meet a bad end, you can be certain that the Pokémon generation will age out of the game and into sullen teendom. The generation that follows will find its own craze. This is too bad, because Pokémon is undoubtedly much smarter and more charming than what will supplant it.

Still, the inevitable death of Pokémon presents us with the opportunity to create the replacement phenom and cash in on it. What transforming, magical game/toy/show will delight the 8-year-olds of the future? I’ve got it! The Netosaurs: A team of dinosaurs that travel through the World Wide Web fighting viruses and eating spam.