U2

U2 was Yugi Mutou's virtual pet and takes after him in appearance.

Yugi and Katsuya Jonouchi interacted their gigapets. Jonouchi's initially bullied U2, but they became friends afterwards.

Kujirada linked his virtual pet with Jonouchi and Anzu Mazaki's and had it eat them. He later tried to let it eat U2, but U2 was able to change into a more powerful form, similar to how Yugi can change into Dark Yugi. This was due to the exchange of data it got from when it interacted with Jonouchi's pet. U2 then beat up Kujirada's pet.

As the virtual pets, usually live an estimated 21 days, Yugi says his goodbyes to U2, the night before U2 was estimated to die.