What if we can’t see it because while energetic it emits less radiation and then will become brighter and hotter as it loses energy? Perhaps it even has reversed entropy too and becomes more energetic over time.
I don't think this would fit the evidence we currently have for dark matter. If it absorbed energy, then it would be much more visible and detectable, as it would often be blocking light and other radiation from objects behind it (at least slightly) and even a slight drop in brightness when dark matter passes in front of something would be fairly easily detectable. (Unless the effect was extremely tiny, I suppose.)
Since that's very similar to methods already in widespread use to search for exoplanets, I think we probably would have noticed variations in star brightness as the amount of dark matter between us and the star varied over time.
As far as we can currently tell, dark matter only interacts with the rest of the universe through the gravitational force. It doesn't absorb or emit any energy. (Except, perhaps, gravitational wave energy.)
Maybe it could work with antimatter instead of dark matter?
Involving antimatter really doesn't help make anything here more plausible.