Board Thread:Questions and Answers/@comment-11452788-20130702111039/@comment-11462520-20130702205727

They weren in the episode "the ultimate sacrifice" for unknown reason. I think that that episode (when all the ultimates try to convince ben to commit suicide to let them free from the ultimatrix) came out BEFORE the first appearance of ultimate wildmutt and ultimate waybig.

They're probably still trapped inside the ultimatrix, but currently, is Azmuth who has it.