I got this event yesterday for the first time. Now that I know what it is, I can handle it, but the first time it pops up, it can ruin a game, and someone's attitute towards it. I came close to uninstalling.
The fact that it came at a critical time in a war where the Arceans started demanding too much tribute and had declared war, then after they realized that just because I was low on the military graph didn't mean that I was a pushover, they formed an alliance with the Alterians, and the next time they attacked, it pulled the Alterians into the war, and the Torians were allied with the Alterians, so they got pulled in too. The Torians were my next door neighbors, so things got messy very fast, especially since I was playing trading empire, and most of my trade routes just got shut down by the sudden expansion of the war.
I'm finally getting a handle on it, and liking it because it was the first time I had fought a full blown war in GalCiv, and it was also the first time it looked like I was going to win with all the AIs set to "Normal." Suddenly, this random event pops up on the only planet in range to support the two starbases I have in that area, both on resources that are critical. If that weren't bad enough, one of the first things that happens is I've got an Overlord charging around blowing away my two starbases, and then it turns towards my empire and goes after my best production planet. Mind you, at this point, only the Torians can make dreadnoughts, I'm the tech leader, but most of my tech is trade-oriented, and I'm at war (through no choice of my own) with them, so I can't get the tech from them so I can throw AM missiles at the Overlord. I tried to fight for a few turns, and then gave up.
I can honestly say that that wasn't fun. Now, if people had called off their wars long enough to put up a fight with the evil, then it could have been fun