To be honest, it will have to be some pretty convincing stuff. Like for the god-creature to come down and appear before me after which he will probably have to convince me why I should worship him as a God, which is an entirely different discussion. The nature of this "God" then would be something I would be very interested in finding out.
I was raised as a Catholic, went to Catholic school and to church when I was young, up until I was 14 or so. For me it always was more of a cultural thing than a strictly religious thing. I was baptized at birth and followed catechesis and underwent Confirmation but I can't say I really believed in the Catholic dogma, or any other for that matter. It was, as I say, more of a cultural and societal thing to do, everyone did it when I went to school. As for the belief if there is something out there, like a god-creature which created the universe and humans (because that is what the theology of the Abrahamic faiths is all about), I can only say that I don't know. There might be something, there might not be and if there is something greater than us, which is entirely plausible, would we consider it (a) God or just a more powerful alien species? (The Aesir were a people humans considered gods but they were not gods to themselves, they were just the Aesir just like you had the Älves and Jötunns. The only reason we see them as gods is because they can do things we can't. Where would be draw the line between powerful alien or God?) The way I look at religion is that it is comforting to think there is a greater purpose to human life than just, the purpose we ourselves give to life, and that is what religion provides for many.
It would be comforting for some and horrifying for others (or perhaps a bit of both), I think, to find proof that we were created by some being for their purposes. It would give us, as a species, a whole other perspective on life.