I know why it happened.
theory time right now GO!:
well zetsu came from underground to get inside kaakshi's body.
cuz of him and obito's sharingan. Madara cast a spell on obito's sharingan.
it made obito see the future of rin getting killed as well as kakashi's tears.
obito said he thought it was rain.
zetsu told him not to worry about images he sees, cuz zetsu knew what was happening.
madara tried ot make it look llike they wanted the sharingan.of kakashi through mist ninja.
part 1 of the theory, do you like
the truth:
Obito Kamui the truth about it:
Madara created Kamui by fusing Zetsu with Obito(after zetsu came from the mazou)
mazou is a space/time specialist since it is a shell of the juubi.all tailed beasts.
while obito was sleeping madara transformed his eye.
when obito / kakashi got mS the same time in the same moment:
they became connected again, and Kamui variation was formed into kakashi's eye because of it.
part 2 theory do you like: im coming up with this on the spot
