I just played with a few guys who found some kind of egg on Forerunner. I think it was legendary in the area with Promethean just before the ghosts. They killed all eneimies in that area , and the area before. After back tracking a few Prometheans spawned, and after killing them insineration cannons fell from the sky. I think I got it right. I told them to post thier find. Maybe they will, and elaborate.
It was also already found in the Discussion thread for the easter eggs
This easter egg has been discovered. But if you did find it without being told how, then congrats. I’d never be able to find something like this, I’ve never really been good at these kind of things.
Also, linky for those who want to see it.