Bio-Savior

After sequencing the alien DNA, a startling revelation was made: the global sea coral network is not only not native to this world, but it is in fact a bio-engineered construct rather than a natural formation. Beneath the thick carpet of alien coral is a fossilized extinction layer of the entire previous ecosystem of this world. It seems the coral, once introduced, gradually choked out all the native life and replaced it with an ecosystem tailored specifically for itself. There are two main theories as to why this might have been done: either the artificial coral was introduced for benign reasons, and then it massively out-competed the local wildlife in an unexpected way, or it was deliberately constructed to be some sort of terrifying biological weapon to cleanse ocean worlds of native life.

The command below will trigger the "Bio-Savior" event in Stellaris:

When this event fires, you can choose between these 2 options:

• Fascinating.
• In adapting, we will suffer no similar intrusions.