Tamagochis!!! I had two or three. I wasn't very into raising the pets though. I had a mermaid one and I thought it was the coolest thing, but I kept forgetting to feed her. This was my 7 or 8 year old self. Anyway, I don't know what happened to her or the dog that I had. I remember how my classmates were so invested in their virtual pets that they'd check on them every few minutes making sure they were alive.