first released in japan by bandai on november 23, 1996, tamagotchi is a handheld digital pet created by akihiro yokoi and aki maita. they are egg-shaped keychains with a lcd screen and three buttons at the bottom which serves as the toy's simple control system. quickly gained popularity in the late 90's and early 2000's, the toy has become a definite landmark of the time. as of march 2021, over 83 million units have been sold worldwide.
the name is a portmanteau of the japanese words "tamago", egg, for the toy's eggshell-like appearance, and "uotchi", watch, due to the original concept of the toy being meant to be worn like a watch (though it can also be interpreted as referring to how you need to watch over and take care of your tamagotchi often i guess lolll)
based off the toy's name, the majority tamagotchi characters have names that end in either "tchi" or "chi" with few exceptions. tamagotchi are explained to be a small alien race that deposited into earth in an egg to see what life was like, and its now up to you to take care of them. the original characters were drawn in a heta-uma (side note: read the article its interesting) style which was them converted to pixel art. character designs are inspired by animals, objects, and people. in later versions, tamagotchi designs have increased in complexity.
the original tamagotchi was marketed specifically for teenage girls. after original release in japan in, a year later in 1997 the "for-boys" counterpart would be released, called the digital monster
even since the explosive popularity of tamagotchis fizzled out, they are still around today and many online communities still bond over their pixel egg pets!