Remember the episodes of Orochimaru's invasion of Konoha.. Primarily his fight with the Third Hokage?... Do you remember the situation?.. it was 3 against 1.

Orochimaru, the First and Second Hokage Versus The Third Hokage. You remember how the third handled that situation?... He summoned the Death God and in return he sacrificed his own life. But wait a minute... He had to make himself a sacrifice 3 times!!!.....

He had Orochimaru to himself and the other 2 HOkage's with KAGEBUSHINS!.... are you telling me that COPY CLONES count as valid instruments when coming to Forbidden Techniques which require sacrifices?.... Makes sense since they're hard copies of yourself.... and if so....

Doesn't that mean that the FOURTH HOKAGE when sealing the FOX could have been a copy himself?.... and in reality.... was under the command of Uchiha Madara,.. and is doing the same at the present with the known alias as PEIN?!?!?!?......

Looks like that's what Jiraiya actually saw... the Fourth in Pein.