If i have yugioh question concerning stardust dragon?

Question

If i have stardust dragon on the field and use its ability to negate the effect of my opponents card on their turn, if they were to use monster reborn to bring it back and used its ability to negate one of my cards which side does it come back to my side or does it just stay in the grave yard because it was not activated by the by the owner?

Answer 1

asuming i hear you right, why would your opponent try to shut themself down?

Answer 2

And the question is?