I've had many memorable campaigns but one moment definitely took be my surprise. Playing on an "X galaxy," the devourer golem played a pivotal role for me in clearing up the AI in the early game. I was eventually surprised that I stopped getting notice on its presence in the galaxy, and after searching for it on on the tab screen, I was all the more surprised to see that it was missing all-together.
So what happened?
I had to go back to an old save to find out. I was playing with nomad planets and successfully armed it against one of the AI homeworlds. Returning to that save, I discovered that the devourer was actually present on the homeworld when I delivered the satisfying planet-sized planet-killer to the AI's front door.
So yeah, there is a way to kill the indestructible devourer golem. Twas glorious.