Unless a civilisation fails to advance past a point or has tight restrictions on what it can do, it will inevitably create a "perfect animal", most likely as a lesser reproducing construct which ends up evolving into one.
A perfect animal is any being that has optimised survival and propogation to the limits allowed by physics, and relentlessly pursues propogation. It fuses elements for energy allowing it to travel at near-lightspeed and destroy anything it sees, and it duplicates itself in moments. As it is capable of extracting all available energy from a star system as it reproduces, any system hosting one of these animals will be rendered completely uninhabitable forever. And all systems in a bubble expanding at near lightspeed.
No effective defence against these animals is possible, it's much easier to destroy than protect, so between a physically perfect attacker and defender, the attacker succeeds.

The only way to survive this threat is for the threat to never exist in the first place. And the only way to ensure the threat never exists is to make a physically perfect being that prevents other perfect beings or any threat to it from ever existing. A hard limit on what civilisations are allowed to do, that can be imposed but never removed. Basically a shitty god, though it could be given more directly benevolent traits to compensate for the potential technology it restricts to itself.
But you'd have to make sure that the entire universe that can be reached and returned from is subject to this god, because what if aliens appear and they carelessly make a perfect animal?
So this begs the question: Could Earth be in the domain of one of these gods?