Jonouchi connected his pet with Yugi Mutou's pet, U2, for a data exchange. As Digital pets commonly took after their owner, Jonouchi's pet began to bully U2, like how Jonouchi used to bully Yugi. The two pets became friends afterwards, similar to Jonouchi and Yugi.
Jonouchi left Joe unattended while he left the classroom. During this time Kujirada fed Jonouchi's pet to his own pet.
When Kurirada tried to feed U2 to his pet, using the data it incorporated from its data exchange with Joe, U2 became more powerful and was able to defeat Kujirada's pet.