virtual pet (toy)
A type of electronic toy with a small LED screen and a few buttons, that displays a pet to be taken care of. Usually hung from a keychain.
Popularized by Tamagotchi and Digimon - this tag covers all virtual pets, including generic depictions that do not directly parody either of the ones mentioned above, and other virtual pets such as the Littlest Pet Shop virtual pet, the Pokewalker, and the Pocket Pikachu.