Title text:
Wait, what do you mean, 'dark matter'? It's not dark, it interacts with high-energy gamma rays ... right? Oh jeez, did I forget to make it interact?
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3263/
In before the antimatter question and the dark matter question are answered by the same mechanism, analogised by antimatter somehow having cloaking technology to avoid annihilation.
Got it: dark matter is Romulan.
Given that it passes through ordinary matter almost entirely undetected, I'd say it was more like the phasing cloak invented by the Federation.
You know, the one that was never heard of again after the episode that featured it.