**(context, skip over if you want)**Imagine a type II alien civilization that spans a large portion of its galaxy. The only reason it’s gotten this far is becuase of their aggression, but there is another. A different civilization that spans most of the known galaxy has had a very bad past with our first one. Our first civilization wishes to take out the second with the help of special equipment that utilize rare dark matter. In my galaxy dark matter is harvested from black holes, so why not take out two birds with one stone by taking out enemy star systems as well as harvesting that juicy dark matter.
This comes to my question: How could an advanced civilization turn a star into a black hole?
Things to consider: Whatever type of contraption that has the ability to do this must not be extremely vulnerable, as it may face combat.
This civilization has access to a multiple Dyson sphere’s worth of energy. Essentially resources are not much of an issue (just don’t go too crazy.)
I’m ok with a little bit of handwavium
Please feel free to give feedback, ask questions, and give advice.
Edit: ok so I probably should have explained this. Regarding your comments I do know that dark matter is common and I know it’s probably not a good idea to get it from black holes, but, in my universe there are two kinds of dark matter: positive and negative. Positive makes up the known universe, its useful but not nearly as useful as the negative dark matter which is almost impossible to harvest without black holes.
Also, my question was “how to turn a star into a black hole” ,not something asking for a lecture about dark matter which we don’t even know that much about.