I need help with a story.

[ditzymusiclover.livejournal.com]

I'm writing a story in the 07 verse, and I need something drastic that Starscream could do to threaten both Earth and (the dead) Cybertron. And it needs to be big enough to require the need of Primus. Things I don't want are a black hole not copying Cybertron or Unicron. Though canon to my knowledge has never had Unicron and Primus duke it out. Suggestions would be really appreciated. Thank you.