I had a big v-pet hyperfixation that's mostly died down, but I still wanted to make this thread for discussion, because there's so much to love about them!
What is a vpet? VPet stands for "virtual pet", and usually refers to LCD devices where you take care of a, well, virtual pet! There's a focus on raising, taking care of, and keeping your pet alive. The most popular examples of these are Tamagotchi and Digimon, but there's many more niche ones. I'm mostly a Tamagotchi fan, but I also like the Pokewalker and Pocket Pikachu.
As a conversation starter: what vpets do/did you own? Whats the most interesting vpet to you?
I own 4 vpets right now: A Tamagotchi Connection V4, a Tamagotchi 4U, a Tamagotchi Uni, and a Pokewalker. Admittedly, I struggled to take care of any of my vpets (save for the Pokewalker) since the system didn't really care about them like I did xP.

One of the most interesting vpets to me is the Japan-exclusive Mothra Tamagotchi, due to the 20+ year mystery of how to unlock one of the secret characters.

This is the Mothra growth chart: All you need to know is the characters on the righthand side are all secret characters. Moru & Mora (anglicized as Moll and Lora), in 26 years, had not been raised by a single person. Iirc, not even a single person had a picture until a year or two ago where a glitch caused the character to be unlocked. Not far after, the Tamagotchi's ROM was dumped and people started to look under the hood to see what on Earth would unlock the character.
An Internet user named Rhubarb Pie was the one to crack the case: To unlock Moll and Lora, you have to make 0 mistakes and have the previous stage's weight maintained between 70-79 tons for 80 Waking Hours. This is, if you don't know, a fairly long time for a single evolution, especially one after the final stage. You then have to make mistakes until the Tamagotchi dies, and only then will it evolve until Moll & Lora.
That's not all that was found by searching the ROM, however: There is an even more secret character, not mentioned or discovered at all until then. If you do the process to unlock Moll & Lora five times in a row, on the fifth attempt it will instead evolve into the community-named Lucky_Haka-Kun, which looks like the gravestone seen in the Mothra Tamagotchi's death screen. This entire process takes more than 17 days of perfect care.
It's so interesting, cause it opens up the possibility of other secrets like this in older Tamagotchi!! I hope you enjoyed learning a little about it :P