Now, Bandai—the Japanese toymaker that invented the Tamagotchi in 1996—has reimagined the Tamagotchi for a new generation. It's introducing the Tamagotchi On, a new version of the classic toy.

Tamagotchis, the egg-shaped virtual pets that were the obsession of kids and the scourge of many parents and teachers in the late 1990s, are making a comeback. Here's how the originals helped ...