This fits the challenges and links it is associated with, and I love the imagery of it.
It may be hard to use in many Sci Fi campaigns due to the difficulty of anyone encountering these beings, but I think it could fit well in a Supers game, if you have heros in the Superman/Silver Surfer level of power available. Go to Comment
Since in most fantasy campaign, detailed knowlage of magnetics would be metagaming, I find this puzzle a bit out of place and overpowered. Again, I have to ask the question "Why was this made?". Go to Comment
Animals have parasites and diseases, so do plants, there are even bacteria that cann dissolve oil spills or plastic or what have you - why couldn't there be a disease living off magic - a magic item could be infected, losing power and speading the plague to other equipment it contacts, while a magic user would slowly lose his powers and contaminate all he works with or casts a spell at...