Like the Furby, this '90s relic simulated owning a pet -- a pet more prone to dying than a carnival goldfish during Rush Week.
If you've ever dreamed of cleaning up the virtual excrement of a chirping, battery-powered, egg-shaped key chain, then rejoice: You're clearly not alone, because these electronic "virtual pets" sold like hotcakes.
Japanese toymaker Bandai first unveiled "Tamagotchi" -- a portmanteau of the Japanese word for "egg" and the English word "watch" -- in 1996. It worked like this: You turned the Tamagotchi on, gave it a name and then used the buttons on the device to feed it, play games with it, put it to bed or, yes, clean up its waste. Over time, the creature on the black-and-white LCD screen would grow and change into different versions -- if you took good enough care of it, that is.
The earliest Tamagotchi required near-constant attention or they would "die," mandating a reset of the device so the process could start over. This made them unpopular with parents and teachers, who noticed their kids sometimes cared for the toys at the expense of chores and homework.
At one time, Bandai estimated it was selling a Tamagotchi per second. More than 70 million have been sold since then, spawning a slew of imitators [source: Takahashi]. The virtual varmints are still available, and elementary school kids can still be seen toting them on their backpacks, though not in the numbers they once did.
Now, for the final item on our list of the ludicrous and lucrative: It's not electronic, but it's probably the original virtual pet -- and it made its inventor a millionaire almost overnight.