Self awareness or the Hard Problem of Consciousness has been extensively debated by scientists, psychologists and philosophers. So what I (or anyone else, for that matter) can provide here is not a definite answer, but only an opinion based on common knowledge and some assumptions.
Self awareness is a property somewhat different from intelligence. A mycelium may be self-aware right now, for all we know. Some religions believe that this indeed is the case and every creature possesses a soul that makes them self aware. From a scientific point of view, we do not know if other organisms are self-aware like we are, but it is often assumed since we evolved from them. Of course, for this to be said, we have to make the assumption the we ourselves are self aware.
Intelligence, on the other hand, is something that can be quantified. We have a pretty good idea as to which creature has how much intelligence based on their behaviour, as well as studying their nervous systems.
Returning to your question... If you have said that mycelia are capable of fighting against humanity, you've granted them intelligence and power. Self-awareness, probably similar to humans is also required, but that is only a small condition. 693
Now that they are an intelligent species , we can raise the usual questions:
1. How intelligent are they? Equal to humans, way ahead of us, or slightly ahead?
2. Do they have the same physical form as actual mycelia or is it different?
(a) Do they have an intricately developed nervous system like a human? Is it microscopic? Or are you granting them intelligence by magic, without altering their physical form?
(b) How much physical strength do they have? For example, even if they knew how to create a nuclear weapon, they may not have the physical strength to actually build one.
3. What knowledge have they acquired so far? It is likely that a species with similar intelligence and different physical form from humans (not to mention a different environment and differently abled physical senses of the organisms themselves) will have evolved a different social system and culture, as well as different levels of knowledge in different scientific fields.
4. What inherent psychological rules are they genetically designed to follow? For example, humans tend to perform activities for personal luxury. They desire fame, power and love in varying amounts. They naturally detest pain. They have instincts that cause them to be nervous in specific scenarios and frightened in others. Is any of this true for the species? 335