Plastic clogs. Ugly teeth. A rock in a box.
It's not easy to predict what will resonate with people.
But these wacky, hot-selling 10 products — part of Thrillist's list of million-dollar inventions — offer something human: a friend (albeit inanimate), playtime and the chance to be a little weird.
Tamagotchis, egg-shaped cyberpets that need to be nurtured and fed, have been a part of childhood for 20 years now. The lifespan of the virtual pet, from when it hatches out of an egg to when it grows wings and "returns to its home planet," is just a few days long.
Bandai America, the toy's parent company, has sold more than 80 million units worldwide. Total sales are around $900 million. The company recently released a miniature digital pet.
In 2002, Colorado-based shoe company Crocs sent its plastic clogs into the world. Since then, it has sold more than 300 million pairs across 90 countries.
Looks like the haters — there's a web site ihatecrocs.com — haven't won yet.
"Peggy Gallagher, an early trader, discovered that the Beanie craze hadn't hit Germany yet and placed an order with a distributor in Nuremberg," according to a 2015 New York Times story. "She paid $2,000, including shipping, for a box of the toys that, back in the United States, had a value of $300,000, a return of nearly 15,000 percent."
Profits were $700 million per year at one point. The owner of the stuffed-animal company, Ty Warner, is now worth $2.8 billion.
But the bubble burst: A Beanie Baby could easily be yours for $5 today.
The Slinky was inducted into the Toy Hall of Fame in 2000. Invented by accident by engineer Richard James in the 1940s, more than 350 million Slinkys have been sold today.
"We view the Slinky as clearly an American icon," Ray Dallavecchia Jr., president of POOF-Slinky, told USA Today in 2012. Dallavecchia said his company has an annual growth rate of 20 percent. Today, total profits are around $3 billion.
Ever since the Chia Pet hit stores in the 1970s, gadget company Joseph Enterprises sells 500,000 of the grow-it-yourself creatures every year. Profits are undisclosed, but each Chia sells for $16.
The pets stay relevant. The company sells figures of presidential candidates and calls it a "Chia poll." Although most political polls leading up to the 2016 election showed Hilary Clinton leading, the Trump-Chia made up 77 percent of sales, compared with just 23 percent for Hilary Clinton.
The late 1990s broke out in a Furby frenzy. Almost 2 million Furby dolls sold in 1998, followed by 14 million the next year. At peak demand, people could buy these weird-looking animals for around $35, and then sell it on the secondary market for up to five times the price. Annual revenue during those in-demand years was at $500 million.
The rock in the cardboard box, along with a 36-page pet-care manual, made creator Gary Dahl a rich man. He sold more than 1.5 million Pet Rocks, which he bought for a penny and sold for $4 each.
''I put about $5 million of today's money in my pocket,'' Dahl told The New York Times in 2004.
The unconventional ball, released in the 1980s, was a major success. Hasbro bought the company that created Koosh Balls, OddzOn, for $100 million in 1997. There was even a book written about the balls in 1989, "The Official Koosh Book." And the rubbery balls made it to Time magazine's list of 100 greatest toys.
Even though its launch was in the middle of the 2008 financial crisis, the infomercial-advertised Snuggie prompted millions of Americans to pull out their credit cards. Rob Walker, in The New York Times Magazine, called it the "Pet Rock of the Depression 2.0 era."
Today, more than 30 million of the body-blankets have been sold. The company that created the Snuggie, Allstar Products Group, has made more than $500 million.
Rotting teeth are in high demand. Jonah White, creator of Billy Bob Teeth Inc., has sold 20 million of them. The company has made more than $50 million in profit.
"Ninety-nine percent of people told me I was a fool and I'd be out of business in no time," White told St. Louis Magazine. "I had no doubt it would be huge."